With President Bush threatening to veto multiple spending bills this year and House Republicans rallying to his cause, Senate GOP appropriators are coming under increasing pressure to help their party present a unified front as they seek to reclaim their traditional footing as fiscal conservatives.

“I think the leadership views this sort of as a litmus test of our ability to lead and govern according to our principles,” said Senate Chief Deputy Minority Whip John Thune (R-S.D.).

“So I think you will see more and more, probably, conflict on approps bills than you have in the past, even among Republicans, because there are going to be a lot of Republican conservatives pushing our leadership to say to appropriators, ‘You can’t be spending over the limits.’”

Still, it remains to be seen how far Republicans on the famously clubby Senate Appropriations Committee will go toward pushing back against bills they helped write and which are likely to carry millions of dollars in earmarks for their states.

But the pressure is on, given that the White House has indicated Bush may veto as many as nine of the 12 annual spending bills because Democrats are on track to spend $21.2 billion more than the president asked for in fiscal 2008.

While House Republicans convinced 147 Members, including a significant number from the House Appropriations Committee, to sign a letter pledging to uphold the president’s vetoes, Senate GOP appropriators indicated they would make their decisions based on the circumstances.

“I think it’ll be a bill by bill fight,” said Sen. Judd Gregg (R-N.H.), the ranking member on the Senate Appropriations subcommittee on State, foreign operations and related programs.

Gregg noted that it would be easy to sustain a veto on the Labor, Health and Human Services, Education and related agencies bill, for example, because it would spend almost $9 billion more than Bush requested. But he said, “Homeland Security will be more difficult” because of the president’s push for an immigration bill that authorizes millions in new spending on border security and other enforcement efforts.

“I think [the White House has] put themselves in almost an untenable position on that bill,” Gregg said of Bush’s recent threat to veto the House version of the Homeland Security spending bill.

Meanwhile, conservatives such as Sen. David Vitter (R-La.) said they have been having discussions about how to make sure they can sustain vetoes on the Senate side.

So far, only one GOP Member of the Senate Appropriations Committee — Sen. Larry Craig (Idaho) — has registered a “no” vote on any of the four spending bills that have been considered by the panel during the past two weeks.

Craig, who voted against the military construction-Veterans Affairs appropriations bill in both subcommittee and full committee, said Democrats are increasing spending levels on feel-good programs simply for political gain.

“A lot of these proposed levels of spending cannot be responsibly expended in a fiscal year,” Craig said. He added, “It is obvious to me that there is more of an intent on a political level than there is the reality of need.”

However, others appropriators, such as panel ranking member Thad Cochran (R-Miss.), have expressed dismay at the Democrats’ decision to set their spending limits $21.2 billion higher than the president’s request, but have yet to vote against a bill.

“I had to notice that the Homeland Security appropriations bill that we marked up the other day was $2.25 billion over the president’s budget request, and I made an observation this morning at our markup on the Interior appropriations bill in subcommittee that we … don’t need to provoke vetoes,” Cochran said Tuesday.

Thune said the initial signs that Republican appropriators are speaking out against the Democrats’ spending plan are encouraging.

“It used to be — whether you were a Republican or a Democrat — if you were an appropriator, everybody stuck together,” Thune said. “I think that’s changing a little bit. I don’t think we’re there yet, but there’s definitely a crack in that solidarity that used to exist on the Appropriations Committee.”

Thune added that Republican appropriators may be “reluctant to bring about change,” but said they recognize that re-establishing the GOP as the party of fiscal responsibility is a worthwhile effort.

Indeed, Cochran has noted several times that he believes Democrats are making the traditionally consensus-based process more political.

“We have been able to work in a bipartisan way in years past, but the Democrats seem to be intent on creating a partisan conflict,” Cochran said. He added that Democrats should not take the president’s vow to veto bills lightly.

“It’s not a threat. It’s a promise,” he said. “I think it’s in our interest to work with the president to get our work done and not create this inevitable gridlock, which is what it will be.”

Multiple vetoes of spending bills very likely will prevent the new Democratic-led Congress from making sure appropriations are in place prior to the Oct. 1 start of fiscal 2008.

Still, Sen. Bob Bennett (R-Utah), the ranking member on the Appropriations subcommittee on Agriculture, said he believes Republicans and Democrats will continue to work together, and he criticized GOP conservatives who vilify appropriators as overspenders.

“I do not concede the fiscal conservative title to some non-appropriators,” Bennett said. “They like to create the notion that if you’re an appropriator, you’re automatically a spender. And then they come around and ask us for help in trying to get things for their state.”

Bennett and other GOP appropriators said Republicans both on and off the committee likely would try to adjust the bills by amendment when they come to the Senate floor next month.

Democrats said they were making every effort to include Republicans in the decision-making process on appropriations bills, but cautioned that even if the GOP Members of the panel were to vote to override Bush’s vetoes, it likely would not be enough to overcome the 67-vote hurdle.

Sen. Patty Murray (D-Wash.) said she understands that Republicans on the committee are under “a lot of pressure” from the president and conservatives. However, she said the process does not have to evolve into a partisan showdown over spending.

“All of us understand that the White House has drawn a very firm line in the sand,” Murray said. “But we have a long process to go in front of us, and the president is going to have to give on some of this. We’re going to have to give on some of this, and I think the pragmatic people in Congress understand that.”