It can’t hurt McCain to not be on the same side of Russ Feingold this summer.

As the Senate takes up an ethics and earmark reform package this week that Democratic leaders have prepared behind closed doors, the chamber’s campaign finance dynamic duo of Sens. John McCain (R-Ariz.) and Russ Feingold (D-Wis.) could make a return performance on the Congressional reform stage — but on opposite sides.
With conservative Republicans bracing for significant changes to the bill passed by the Senate in February, McCain could end up fighting his former ally in an effort to block a significantly weakened bill.
According to sources close to the issue, Majority Leader Harry Reid (D-Nev.) has called on Feingold to help push the bill over the goal line. Reid hopes Feingold’s progressive street credentials and reputation as a reform-minded lawmaker will help keep the left flank from bolting, particularly if Reid and Speaker Nancy Pelosi (D-Calif.) make controversial changes to the bill.
White House hopeful McCain, meanwhile, already has thrown in his lot with Sen. Jim DeMint (R-S.C.), who has attacked the secretive process Reid and Pelosi have used to rewrite the bill and has threatened to filibuster it if its earmark provisions are changed.
Although McCain’s office did not respond to a request for comment, several of his colleagues in the Republican Conference said it appears likely McCain will make a rare appearance in the Senate this week to back reformers. When asked about McCain’s plans, Sen. Lindsey Graham (R-S.C.) said he expected the Arizonan will return to the Senate this week. “That’s my understanding,” Graham said.
Similarly, DeMint said he has discussed the issue with McCain and that while the two had not discussed McCain’s schedule, “I’d expect him to be here. … This was his issue for a long time.”