Sen. Russ Feingold (D-Wis.) is close to finding the 51 or more votes he needs to attach stringent budget-enforcement rules to the Senate’s 2006 budget resolution when it comes to the floor next week.

For now, Feingold appears to have 50 votes for a “pay as you go,” or PAYGO, amendment that would force Congress to offset mandatory spending increases with new revenue streams and to offset any new tax cuts.

If the amendment is adopted by both chambers, 60 votes would be needed in the Senate to enact any new tax cuts sought by Congressional Republicans and the White House.

So far, five Republicans have indicated they will vote for Feingold’s proposal: Sens. Olympia Snowe (Maine), Susan Collins (Maine), Lincoln Chafee (R.I.), John McCain (Ariz.) and George Voinovich (Ohio).

Without naming which Republicans he was targeting, Feingold said “there may be some additional surprises” in who votes for PAYGO this year.

The effort is considered significant because adoption of PAYGO rules last year essentially prevented the House and Senate from passing a bicameral budget blueprint.

“I think we have a very good chance of getting more than 50,” Feingold said.

Under Senate rules, Feingold must get 51 votes to pass his amendment, because a 50-50 tie would cause it to fail.

Meanwhile, Senate Budget Chairman Judd Gregg (R-N.H.) said he wasn’t sure if he had the votes to stop Feingold. “I presume so, but I don’t know,” he said.

Voinovich opposed Feingold’s amendment last year but is now co-sponsoring a bill with Feingold to implement PAYGO rules.

“If that came up on the floor, yes, I’d vote for that amendment,” Voinovich said.

Meanwhile, at least two other Republican Senators indicated they may be open to persuasion this year.

“I have some interest [in the amendment], but I haven’t decided yet,” said Sen. Mike DeWine (R-Ohio), another Senator who voted against last year’s proposal.

Similarly, Sen. Lamar Alexander (R-Tenn.) did not reject the notion of supporting Feingold this year.

“What I’m trying to do is cut the federal deficit in half,” Alexander said. “So, we’ll see. I’ll wait to see what [Feingold] has to say about it.”

Alexander, a member of the Senate Budget Committee, could make his decision known today, when Feingold offers his proposal during the panel’s markup of the 2006 budget plan. But even with Alexander’s support, Feingold would have to convince one other Budget Republican to vote for the proposal if it is to be approved by the panel — a scenario that is considered unlikely.

GOP leaders in both the House and Senate oppose PAYGO, arguing that it would make it too difficult to pass new tax cuts — a central tenet of their economic policy.

For example, Sen. Gordon Smith (R-Ore.) said he would not reverse his vote against PAYGO this year because Bush’s tax cuts were effective in stimulating the economy.

“The tax cuts are working. Our economy and our revenues are up,” Smith said. “I’m against any device to limit them.”

Feingold garnered 51 votes last year for his amendment, including four Republicans and all but one Democrat. But now that Senate Republicans have increased their majority from 51 to 55, the task of getting the provision adopted involves convincing more GOP Senators to change their votes this year.

In addition, last year, Snowe, Collins, Chafee and McCain killed the bicameral budget package when they demanded that any final budget resolution include PAYGO rules.

Still, even if Feingold garners 51 votes for his amendment, it is far from certain that his Republican supporters will try to force the House to accept the proposal, as they tried unsuccessfully to do last year.

Indeed, Collins, Chafee, Voinovich and McCain said they have not made a decision on whether they would oppose a House-Senate negotiated budget resolution if PAYGO is not included.

McCain said he wanted to see the entire budget package rather than vowing in advance to oppose it based on the inclusion of one provision.

Similarly, Collins withheld her judgment.

“There are a lot of issues that concern me [in the budget], and it hasn’t even come out of committee yet,” she said.

Snowe also is undecided, but her spokeswoman noted that, “PAYGO is absolutely at the center of Sen. Snowe’s outlook on the budget.”