Three presidential campaigns made a rare convergence on the Senate floor Thursday, confronting critical questions looming over their White House bids while casting votes on tax-and-spending issues certain to appear in attack ads in the coming months.

Sen. Barack Obama (Ill.), the Democratic front-runner, wasted no time attacking the presumptive Republican nominee, Sen. John McCain (Ariz.). In a brief interview with The Hill, Obama said McCain’s policy on taxes would “mean mountains of debt for future generations.”

“Sen. McCain originally said they were irresponsible, particularly at a time of war,” Obama said. “He was right then and he is wrong now, and it’s unfortunate that this was the ticket he felt he had to punch in order to win the nomination.”

Brian Rogers, a spokesman for the McCain campaign, punched back, saying that McCain would not support a tax increase like Obama would, “hurting our economy and costing jobs for hardworking Americans.”

The comments capped a rare day of presidential politicking and posturing in the Senate, as all three candidates strategized with their allies and worked on relationships with senators whose campaigning could be critical in the general election. For Obama and his chief rival for the nomination, Sen. Hillary Rodham Clinton (D-N.Y.), each moved swiftly to court the 26 undecided Democratic senators, who are among the superdelegates likely to be crucial in choosing their party’s nominee.

For the first time in history, each party is poised to nominate a sitting senator as its nominee, but the senators’ presence in the upper chamber is becoming increasingly rare amid a heavy campaign schedule. Thursday marked the first time in nearly five months that all three of the senators have been on Capitol Hill on the same day for votes.

On Thursday, Obama and Clinton — who had a brief interaction on the floor — were faced with a slew of controversial votes. But they were also faced with questions hovering around their campaigns, including how to handle delegates from Florida and Michigan. The congressional delegations from Florida and Michigan pressed the candidates to reach an accord on awarding their states delegates after they were stripped by the Democratic National Committee as punishment for the states’ holding early primaries and thereby violating party rules.

Sens. Bill Nelson (D-Fla.) and Debbie Stabenow (D-Mich.), both Clinton supporters, talked at length with Obama over dealing with their states’ delegates. But they could not reach a resolution before Senate Majority Whip Dick Durbin (D-Ill.), a national co-chairman of the Obama campaign, interrupted their chats.

Nelson described the talk as “just an amicable conversation that we’ve got to get this settled.”
In between the strategy sessions, the senators were voting on the floor, casting a series of votes over a fiscal 2009 budget resolution. On nearly every controversial vote, Obama and Clinton were aligned but on the opposite side of McCain.

Those votes created a sharp distinction that both sides acknowledged would be certain to be used against each party’s nominee ahead of the November elections.