WHEN SEN. Mark Warner took to the floor last week to speak on deficit reduction and tax reform, his language, as the Virginia Democrat acknowledged, was not exactly senatorial. It was, Mr. Warner said, time to "put up or shut up." The senator said he planned to vote for this year's tax package - adding $858 billion to the national debt. But, he argued, "We also have to demonstrate that this body can actually walk and chew gum, that we can do short-term stimulus now, but next year engage in meaningful tax reform and deficit reduction."

Key words: next year. Not 2012, and certainly not 2013.

It's significant that Mr. Warner was not playing lone deficit ranger. Together with Georgia Republican Sen. Saxby Chambliss, Mr. Warner assembled an impressive posse of 18 senators - eight Republicans and 10 Democrats - to go to the floor to underscore what President Obama might call the fierce urgency of deficit reduction and tax reform.

Might, that is, but hasn't. Mr. Obama seems to be moving in the right direction, but when he talks tax reform, he phrases it in terms of a leisurely "conversation," as in his recent interview with National Public Radio: "We're going to have to have a conversation over the next year. . . . And if you think about the last time we reformed our tax system back in 1986 - it didn't happen right away, by the way. It required a lot of conversations among a lot of different parties."

Yes, tax reform would be a heavy lift, especially in a Republican-controlled House whose members have shown no willingness to consider raising tax revenue even in the context of spending cuts. Democrats who are equally rigid on entitlement reform add to the challenge. But if the president is tempted to push tax reform beyond the 2012 election or to seek only baby steps, such as an overhaul of the corporate tax code, we hope he thinks again. Delay will only make the eventual solution more painful and more costly. "We've got to address this and we've got to address it next year," Mr. Chambliss said.

We agreed with Mr. Warner that the faltering economy on balance justified this year's tax deal - but only with the proviso that lawmakers and the administration make a quick pivot to long-term deficit reduction. Days before taking office, during a visit to The Post, Mr. Obama assured us that he understood the urgency of tackling entitlement spending and reducing the long-term deficit. "What we have done is kicked this can down the road. We are now at the end of the road and are not in a position to kick it any further," he said. "We have to signal seriousness in this by making sure some of the hard decisions are made under my watch, not someone else's."

An economic crisis at that time justified even more deficit spending. Then Mr. Obama turned to health reform, in part on the theory that changing health care was the only way to get entitlement spending under control. After that came a bipartisan commission on the debt, which produced a useful debate and encouraging signs of bipartisanship. Now comes the moment for him to demonstrate that he meant what he said nearly two years ago. The emergence of the Warner-Chambliss caucus suggests that the president will have political backup if he mounts a serious effort.

From the Washington Post