The decision by House Democratic leaders to attach a debt-ceiling increase to the Defense spending bill has pitted the GOP’s fierce support of the military against its pledge to be fiscally responsible.

Many Republicans have previously voted for measures they would not have otherwise supported because they were attached to defense-related bills, but the provision to raise the debt ceiling to at least $1.8 trillion appears to be a bridge too far.

“I don’t think any Republican will vote for it,— said Rep. Buck McKeon (R-Calif.), ranking member of the House Armed Services Committee. “They are starting to follow a pattern — putting everything that is an anathema to Republicans on the Defense bill, knowing we all will support the troops.—

“They have probably taken this one step too far,— he said.

McKeon was one of 44 Republicans that chose to vote with Democrats earlier this year to pass the 2010 Defense authorization conference report. The bill included a provision to expand the definition of federal hate crimes to include attacks based on a victim’s sexual orientation, gender identity or mental or physical disabilities and was opposed by 131 Republicans.

“It’s hard to vote against it,— McKeon said of the 2010 Defense appropriations bill. “The people know where we are, the people know Republicans support the military.—

“It’s kind of sad,— Rep. Duncan Hunter (R-Calif.) said. “Military [spending] should be its own deal. It should be a stand-alone — especially during wartime.—

Hunter, a former Marine captain who served in Iraq and Afghanistan, said he would not need to explain his “no— vote to his constituents.

“They know if I’m voting against it there is something extremely wrong,— Hunter said. Rep. Candice Miller (R-Mich.) said the decision was difficult, but she would vote “no— if the debt ceiling is attached to the Defense bill.

“I just think it is so outrageous to put on this rise of the debt ceiling on the backs of the troops,— she said. “If they do that, I’ll be voting ‘no.’ I just can’t choke it down.—

The lack of Republican support on a defense-related bill has been a problem at least once for House Democrats.

In June, 32 Democrats — many of whom are members of the liberal anti-war caucus — joined 170 GOP lawmakers to vote against the $105.9 billion war supplemental.

While the ideologically opposite groups voted against the bill for completely different reasons, the effort nearly brought down the bill. The war supplemental narrowly passed the House, 226-202.

But since Democrats announced last week their plan to attach the debt-limit hike as well as a new jobs package to the Defense bill, leaders have taken several steps to ensure there are few defections within their ranks.

In order to get conservative Blue Dog Democrats on board with the debt-ceiling increase, Democratic leaders attached language enshrining pay-as-you-go rules into law.

Several anti-war Democrats have also said they are pushing their leaders for separate votes on war and domestic spending in the conference report, which could give Republicans an opportunity to vote for the troops but against the add-ons.

Democrats have done that previously when war funding was at stake, although Democratic leaders said they aren’t certain it will be necessary this time around.

“I hope to separate the part with the war funding,— said Rep. Raúl Grijalva (D-Ariz.), who co-chairs the Congressional Progressive Caucus. “The bill’s not going to be clean to begin with.—

If the vote on war spending is split from the domestic spending, Republicans will almost certainly reject any nondefense-related add-ons.

In a letter on Friday afternoon to Speaker Nancy Pelosi (D-Calif.), House Republicans asked that the chamber be allowed to vote on a clean defense-spending bill.

“We object to maneuvers to use our troops as leverage to enact proposals that the Majority either cannot pass on their own or for which they wish to avoid directly voting on and we will oppose a Defense Appropriations package that includes such provisions,— the letter said.

A House Democratic senior leadership aide said plans for how the bill would be brought to the floor are still under discussion and accused Republicans of unnecessary theatrics.

“Even though no final decisions have been made, Republicans are already grandstanding with America’s financial solvency and threatening to play politics with our troops,— the aide said.

Another leadership aide said the Republican strategy isn’t surprising.

“They have been finding excuses to vote against the military and troops all year long, why would they get religion now?— the aide asked.