The debt-limit debate is heading toward a culmination, with President Obama reduced to pleading for the public to support a tax increase and Speaker John Boehner and Senate Majority Leader Harry Reid releasing competing plans that are the next-to-last realistic options. The question now is whether House Republicans are going to help Mr. Boehner achieve significant progress, or, in the name of the unachievable, hand Mr. Obama a victory.

Mr. Obama recognizes these stakes, threatening yesterday to veto the Boehner plan in a tactical...