All four GOP candidates for governor made it to the second 9NEWS Republican debate before the June 26 primaries - the first happened in April. The candidates argued over who had the best chance to win in November and one another's credentials and demeanor.

This debate comes three days after the Democratic candidates met on the same stage and a little under three weeks until the primary narrows the field of big party candidates to two.

READ MORE | Colorado’s June primary election: what you need to know

Former Parker Mayor Greg Lopez, former State Rep. Victor Mitchell, businessman Doug Robinson and current State Treasurer Walker Stapleton spoke for an hour about their vision for the future of the Centennial State.

9NEWS anchor Kyle Clark and political reporter Brandon Rittiman moderated the debate. They also chose the format and questions.

These debates have taken on a new light since, for the first time in history, unaffiliated voters will be allowed to participate in the party primaries.

PREVIOUS DEM DEBATE | What happened during the Democratic gubernatorial debate

PREVIOUS GOP DEBATE | What happened during the Republican gubernatorial debate

On Sens. Gardner and Warren's bipartisan bill to protect states that have legalized marijuana

None of the candidates particularly supported Sens. Cory Gardner (R-Colorado) and Elizabeth Warren (D-Massachusetts) effort to shield states from federal laws prohibiting the sale and consumption of marijuana. Stapleton was most for it.

MORE | Gardner, Warren introduce bill to safeguard states with pot

Robinson said the legalization of marijuana had a lot of unforeseen complications for Coloradans. He wants the state to do a better job of getting as many tax dollars as possible.

Mitchell agreed with Robinson and would support a repeal effort on the recreational side.

Stapleton said it's not reasonable to support the removal of recreational pot sales from the state, pointing to the litany of states that have legalized it. He said the medical side of marijuana states needs to be looked it, a claim echoed by several of his colleagues on stage.

Lopez said he supported putting the question of legalized marijuana back to voters.

On the issue of immigration in Colorado and deporting non-criminal undocumented immigrants

Stapleton was asked how he would end sanctuary cities (cities that don't cooperate with federal immigration agencies) and answered by pointing to how bad Democratic Rep. Jared Polis (D-Boulder) would be for the state if he were elected.

When pressed, he explained that he would take away any state funds for infrastructure earmarked for the sanctuary city.

BACKGROUND | Larimer sheriff sits down for sanctuary city discussion after meeting with Trump

Stapleton, Robinson and Lopez said if elected they would assist President Donald Trump by sending members of the Colorado National Guard to the border with Mexico if asked. Mitchell said he would not.

Mitchell said he wants to hold sanctuary cities civilly liable for any crimes committed by undocumented immigrants. Neither Lopez nor Robinson would. Stapleton said he would if he could.

All but Stapleton agreed that undocumented immigrants with criminal records would be their focus when it came to deportations. Stapleton spoke about deporting anyone who was in the country illegally and then said he wouldn't answer a hypothetical.

On Stapleton's (and, to a lesser extent, Lopez's) history with alcohol

Both Lopez and Stapleton have had run-ins with the law related to alcohol. Lopez had a domestic violence arrest and Stapleton a DUI. Our moderators asked Stapleton about his history with alcohol and what his relationship was now.

Stapleton said it was 28 years ago and he made a mistake. After a few prods from the moderators, he said he'd describe his relationship with alcohol as "responsible" since he has kids now.

He then transitioned into talking about how bad Polis would be for the state.

On the Supreme Court's recent ruling and protections for people of differing sexual orientations

All candidates agreed the court made the right call when they took the Colorado Civil Rights Commission to task for going after the Lakewood baker who refused to make a wedding cake for a gay couple because it was against his religion.

When asked if they would sign a bill removing protections for people of differing sexual orientations from Colorado ordinances, none said they would sign it.

BACKGROUND | SCOTUS ruled against Colorado Civil Rights Commission in baker case; so who are they?

Robinson said it was important to remember religions are protected, too. Lopez said he would never want to take rights away from Americans. Mitchell said he was disappointed in how litigious people are and wants to solve things without the courts. Stapleton said the essence of the Supreme Court decision was that people shouldn't be discriminated against.

On the question of if Lopez has any policy positions

Our moderators brought up to Lopez that when he answers policy questions, he doesn't so much answer them as say when he gets elected he'll get everyone in a room and talk it out. Our moderators said at some point it may seem like he doesn't have any policy positions.

Lopez said when he was Parker's mayor he had to deal with a host of issues. He explained that candidates can talk about what they want to do or what they would do all they want - they just won't really know what they can do until they get the job. He said he's someone who sits back and takes all the information in before making a decision.

According to Lopez, that's what the people want.

On fixing Colorado's pension system

Our moderators questioned Stapleton's commitment to reforming the state employee pension system, as he missed a meeting about it nor did he go to the Capitol when they were voting on a bill to change it.

BACKGROUND | Hickenlooper signs pension-reform bill; vetoes 2 measures

Stapleton replied by saying that he had a representative at the meeting he missed and already knew what the meeting's context would be. He also said he was on the phone with lawmakers the night they were voting on PERA reform, urging them to support it.

Robinson openly disputed that and said he spoke to lawmakers who said Stapleton told them to vote against it.

Stapleton denied the claim.

On being a "Never Trumper"

Some members of the Republican Party were against their candidate for president in 2016: Donald Trump. Mitchell has attacked Stapleton as a "Never Trumper," the nickname people against the president have been given. Mitchell has said he didn't vote for Trump.

Our moderators wanted Mitchell to explain how he can run ads painting Stapleton as anti-Trump when he's been forthright about being the same thing.

Mitchell mainly pointed to Stapleton's familial bonds as the reasoning behind that; Stapleton is related to the Bushes, who were openly anti-Trump during the 2016 campaign.

Despite our moderators pointing out people have family members with differing political views from them, Mitchell stayed the course and called Stapleton a hypocrite and accused the treasurer's whole family of not voting for Trump.

Robinson came in at that point to say Mitchell asked him for a meeting with Mitt Romney - the former presidential candidate and "Never Trump"-er who also happens to be Robinson's uncle. The point of the requested meeting, Robinson said, was to get in touch with donors who would help Mitchell with his "Never Trump" movement.

Stapleton then pointed out Mitchell donated to one of Trump's opponents.

On Robinson's "nice guy" image and the history of GOP candidates with scandals

Our moderators wondered if, in the age of popular GOP candidates with scandals, Robinson could hope to win as a "friendly, mild-mannered guy with no scandals."

Robinson said he's lived his life to conservative values and thinks that resonates with voters.

On the "Deep State" and what the candidates may face if elected

Our moderators pointed to the president's many assertions that a "Deep State" conspiracy was working to undermine him at every turn. The conspiracy members were regular government workers and others who were spies for the opposition. Our moderators wondered if the candidates believe such a thing was real and if they believed it on a state level.

Only Mitchell and Lopez acknowledged it in Colorado. Lopez said it was some state workers but couldn't say how big. Mitchell said there was absolutely a "Deep State" in Colorado already, pointing to sheriff's offices holding records on people who were accused -- but never charged -- with a crime.

To raise the sales tax or search for state money to improve Colorado's infrastructure?

Two proposals may go to the voters of Colorado in November to pay for infrastructure improvements. One would raise the sales tax and another would raise no new taxes but task state officials with finding funds for the roads.

Our moderators wondered which, if any, the candidates supported.

Mitchell said he doesn't support any new taxes and trashed the Colorado Department of Transportation as "the worst bureaucracy in the state."

Robinson said he was glad there's focus on this issue and said he didn't support the sales tax.

Stapleton said if Polis was elected there wouldn't be any money left to pay for roads.

Lopez said he didn't support the sales tax either.

The 2030 Olympic Games to Denver?

Current Colorado Gov. John Hickenlooper and Denver Mayor Michael Hancock have come out in favor of trying to bring the 2030 Winter Olympic games to the Mile High City.

Robinson and Stapleton said they wouldn't support it unless there could be a guarantee no taxpayer funds would be used.

RELATED | Committee recommends Denver bid for future Olympic Games

Our moderators pointed out the International Olympic Committee has never guaranteed that in the past.

Lopez was against the games completely.

Mitchell said we should consider looking at the games but they would have to be brought in "cost feasibly."

On the candidate's thinking regarding the "Red Flag bill"

Our moderators brought up the Red Flag bill that recently died in the state legislature. It would take firearms away from people who were deemed a danger to themselves or others by a judge.

Each candidate explained they would have liked to see changes to the bill.

MORE | Colorado panel rejects police-supported 'red flag' bill

Mitchell claimed he had an A+ ranking from the National Rifle Association but Stapleton said Mitchell hadn't any grade since he didn't bother filling out their questionnaire.

On Stapleton's campaign ad with the false claim

Stapleton put out an ad a month or so ago claiming to be the only state treasurer to support Trump's tax cuts. Our TruthTest team was able to quickly debunk that - he wasn't the first or the only one.

Most of the GOP treasurers we reached out to had publicly supported it. Stapleton's camp disagreed with 9NEWS' analysis by saying he was the only treasurer mentioned in the White House's press release.

TruthTest | Walker Stapleton oversells Trump bonafides

When asked what he learned, Stapleton said he hadn't learned anything and debated the semantics of the error.

On Lopez's claim the lack of religious values contributing to school shootings

Our moderators pointed to Lopez's claim that at least a part of the reason there have been so many recent school shootings is due to the lack of religious values in the United States.

When asked to clarify, Lopez explained that there's a lack of respect for life in the U.S. He said people need to take care of each other. Some of the ways people act, he went on to say, makes it sound like God doesn't matter or have a role in the country. He said God does matter.

On Trump's loss in Colorado and how the candidates will be different

Robinson said Trump lost because he couldn't bring in independents and conservatives together - Robinson said he thinks he could if he was the party's choice for November.

Stapleton said he wasn't a pundit and wouldn't try and figure out why the president lost and instead said the state needs someone in the governor's chair who would take on Washington when it made sense to.

Lopez said the president lost the state because his message didn't resonate with voters. Lopez wondered aloud how any candidate's message might resonate when they don't respect people.

Mitchell said he wasn't a political prognosticator and that he is able to bring together independents and that's why he'll win.

On the state's efforts to lure Californians to Colorado

Stapleton said it's a fine tactic, trying to bring out-of-state talent to Colorado to fill vacant jobs. He pointed to Utah doing the same to Coloradans. He then attacked Polis again for supporting the repeal of the recent tax overhaul passed in Washington.

Mitchell said he supports the idea but tempered by saying the state would need to make sure it's "smart growth." He said he wants to make sure all parts of the state are feeling the effects of growth - not just the urban centers.

RECOMMENDATION | Californians describe how quaint and cheap they find Denver

Robinson said a lot of Coloradans are feeling the anxiety that the economic boom in the state is passing them by. He said he didn't think state money should be used for the ads and wondered aloud why the state wasn't training its current residents to fill those positions instead of looking to California.

Lopez said the ads send the wrong message; the state doesn't believe in its own children. He wondered how long it would take to train the state's current residents to fill those positions.

On tax incentives for businesses to move to Colorado

Our moderators brought up the nationwide quest for Amazon's second headquarters and the hefty tax incentives pushed by state leaders in Colorado.

Stapleton said he believes the state has an effective plan when offering money to companies that want to move. He called the incentives "earned tax credits" and praised the way they were handled.

Lopez said he wouldn't give any incentives no matter the business and then said he would have to look at each business case by case.

PREVIOUSLY | Denver officials quietly met with the Amazon HQ2 team

Mitchell said he thinks incentives are corporate welfare and said he thought no public money should be going to giant companies like Amazon.

Robinson said if we want good companies in the state this is just one tool in the tool chest to get them here.

On limiting growth and a statewide assault-style weapons ban

When asked if any candidate supported any town in Colorado taking specific steps to limit growth in their municipality, all said they were against such a thing.

The candidates were also equally opposed to a hypothetical statewide assault-style weapons ban.

Closing statements

Lopez began his closing statement of the debate by saying he thought the governor's job was to promote, protect and serve the various ways of life that make Colorado great. He said it's about all of us not just some of us and that he wanted to represent all 64 counties.

Stapleton said he was running for governor because of his kids. He said he wants the Colorado they inherit to be full of economic opportunity. He said if Polis was elected the state would be worse off.

Mitchell talked up his rags to riches story. He said he started his first business when he was 21 and has guided six different businesses to success.

Robinson said the stakes are high in the governor's race and if conservatives wanted to win in November they would need to vote him as their candidate. He said voters should want a clean candidate who didn't have any of the scandals like Stapleton in their past.