None of Colorado’s GOP members of Congress took an anti-Trump stance when asked by 9NEWS whether they would support the billionaire’s insurgent bid for president if he ends up winning the Republican nomination.

National GOP leaders have grown increasingly leery of Trump, with past Republican nominee Mitt Romney going so far as to call the reality-TV star turned politician as a “phony” and a “fraud” who must not become the party’s standard-bearer.

The five Republican members of Congress from Colorado were split along two positions: refusing to answer the hypothetical and saying they would support the eventual GOP nominee.

Sen. Cory Gardner, Rep. Doug Lamborn, and Rep. Scott Tipton all indicated they would support the GOP nominee.

Rep. Mike Coffman and Rep. Ken Buck both declined to answer.

Coffman (who has endorsed Marco Rubio) “is not commenting on a hypothetical,” his spokeswoman Cinamon Watson told 9NEWS, though he did offer some criticism in a written statement.

“If he has any true aspiration of winning the White House, [Trump] needs to elevate his rhetoric out of the gutter,” Coffman said.

“I won’t answer a hypothetical,” Buck said in a statement. Buck has endorsed Ted Cruz who is in second place in the current delegate count.

After being pressed seven times to answer the question by Wall Street Journal, Gardner did say “I will support the Republican nominee” on Friday, saying he didn’t believe Trump would end up with the nomination.

On Monday, Gardner walked that back, telling 9NEWS via email he “will not engage in hypotheticals,” and stating that he believes Marco Rubio is the only person in the race who can prevent Democratic front runner Hillary Clinton from winning the White House.

“Looking at the choice of Hillary Clinton and Bernie Sanders vs the Republican nominee, [Tipton] will support the Republican nominee,” wrote Tipton’s spokesman Josh Green.

It’s become a sticky issue for Republican politicians. Trump has broken the mold for GOP candidates, attracting healthy support from the conservative base despite a checkered past on some hot-button Conservative issues such as abortion and healthcare.

Most of all, Trump has ginned up angry enthusiasm from conservatives fed up with traditional politicians.

Democrats have had to contend with similar pressure from the candidacy of Bernie Sanders, though Sanders has never enjoyed front runner status in the race.

In a recent interview with 9NEWS, Gov. John Hickenlooper (D-Colorado) exclaimed “who knows” when asked whether he’d support Sanders as nominee.

Sanders won the Colorado caucuses on Super Tuesday, but lost in most other states.

As of Monday he was 200 delegates behind Hillary Clinton in state contests, but more than 600 behind when factoring in Superdelegates, the elected officials and party VIPs who are allowed to vote for whomever they wish in the Democrats’ contest.