Senate Republicans have, at least for now, held their fire on a pending Democratic jobs creation bill, hedging their bets should a bipartisan deal come together.

But GOP Senators warned that if negotiations between Finance Chairman Max Baucus (D-Mont.), ranking member Chuck Grassley (R-Iowa) and Orrin Hatch (R-Utah) break down over Democratic demands to add extraneous provisions to the bill, they are prepared to take the gloves off.

A collapse of those talks would signal “that they didn’t learn any of the lessons from health care,” a Senate leadership aide said, adding that Republicans would likely balk at supporting the first of what’s expected to be several economic measures. Majority Leader Harry Reid (D-Nev.) is expected to unveil the first package as soon as today.

So far, Minority Leader Mitch McConnell (Ky.) and other GOP leaders have played nice, withholding attacks on Democrats for drafting the legislation behind closed doors. That posture is likely to continue so long as Hatch and Grassley are at the table, Republicans say.

“We believe jobs should be the top priority. … Most of us would prefer to work with out Democratic colleagues in the middle,” Republican Conference Chairman Lamar Alexander (Tenn.) said Friday.

Alexander also said that the fact that Hatch and Grassley are engaged in the process has “absolutely” helped calm Republican nerves, noting that, “for a while it looked like it was being written like the health care bill.” A senior GOP operative agreed, noting that the package that has been discussed with the two Finance Republicans includes a host of provisions favored by the minority, including tax credits for small businesses.

“The reason it’s a ‘keep your powder dry’ situation is because there are a lot of elements that we know we need to get done and that we as a Conference are nearly unanimous if not unanimously for getting done,” the operative said.

Democratic aides familiar with the jobs legislation said that at this point, the “jobs part” is likely to include small-business tax breaks, Build America Bond language, unemployment insurance and COBRA health insurance language and an extension to the highway bill, as well as a handful of tax extenders.

All of those provisions enjoy wide bipartisan support, and a second GOP leadership aide said if the bill remains narrowly focused on those issues, “it could get 80 votes.”

Less clear is what if any non-job-related provisions will be tacked onto the bill Reid introduces this week. Reid had hoped to announce a bipartisan bill late last week but postponed the unveiling as negotiations with Republicans continue.

Reid reportedly has provided Republicans with a much broader version of the legislation. For instance, Baucus said Thursday that a “doc fix” to continue Medicare payments to doctors as well as other smaller Medicare provisions “are being discussed” as possibilities.

And while those issues may not stir up major GOP opposition, other provisions might.

For instance, the blueprint provided to Republicans also included a section reauthorizing the USA PATRIOT Act, which Judiciary Chairman Patrick Leahy (D-Vt.) has pushed Reid to include, GOP and Democratic aides said. Republicans said that and other measures unrelated to jobs should not be included and that if Reid insists on pushing the legislation through as a massive catch-all for Democratic priorities rather than a narrow jobs bill, the bipartisan spirit will quickly extinguish. “It’s hard to sympathize with that” approach, the GOP operative said, complaining that Reid has allowed his chairmen to exercise too much influence over the bill.

“He gives his chairmen a lot of leash and they push the legislation in a different direction than he wants,” the operative said.