Suddenly, the World’s Greatest Deliberative Body, the U.S. Senate, is full of meaningful activity this week, thanks to the annual debate on a congressional budget resolution. Today Bill Nelson of FL offered a sense-of-the-Senate resolution expressing opposition to any Social Security proposal that involved “deep benefit cuts or a massive increase in debt.” It failed on a 50-50 vote, but as Sam Rosenfeld noted at Tapped, its big-tent wording not only attracted support from every single Democrat and five Republicans, but also put 50 GOPers on record as having no problem with “deep benefit cuts or a massive increase in debt,” a gift to Democrats that will keep on giving for many campaigns to come. And it was a particularly smart move for Nelson, a prime target for Republicans in 2006 in a state where messing with Social Security is just not something you want to do. But as Mark Schmitt of The Decembrist has explained, the Senate will consider another amendment tomorrow with perhaps bigger implications: an amendment to the budget resolution cosponsored by Democrat Russ Feingold and Republican Lincoln Chafee that would reimpose pay-as-you-go (PAYGO) rules for spending increases AND tax cuts. This amendment would block the current administration/GOP leadership effort to extend some of the 2001 tax cuts without offsetting spending or revenue measures. If it passes–probably an even bet at this point–PAYGO might well replicate last year’s House-Senate Republican impasse over the budget resolution, which means GOPers would not be able to ram through their specific budget plans (not only tax cuts, but some nasty spending measures, especially on Medicaid) without the usual 60-vote requirement to avoid a Senate filibuster.In other words, this is a key step in unravelling the whole Bush legislative agenda for the year, and in stopping the insane tax and fiscal priorities that will eventually disable our government from doing much of anything to meet big national challenges. The vote tomorrow merits some real attention and energy.