The Republicans have changed American politics since they took control of the House of Representatives. They have put spending restraint and debt reduction at the top of the national agenda. They have sparked a discussion on entitlement reform. They have turned a bill to raise the debt limit into an opportunity to put the U.S. on a stable fiscal course.

Republican leaders have also proved to be effective negotiators. They have been tough and inflexible and forced the Democrats to come to them. The Democrats have agreed to tie budget cuts to the debt ceiling bill. They have agreed not to raise tax rates. They have agreed to a roughly 3-to-1 rate of spending cuts to revenue increases, an astonishing concession.

Moreover, many important Democrats are open to a truly large budget deal. President Obama has a strong incentive to reach a deal so he can campaign in 2012 as a moderate. The Senate majority leader, Harry Reid, has talked about supporting a debt reduction measure of $3 trillion or even $4 trillion if the Republicans meet him part way. There are Democrats in the White House and elsewhere who would be willing to accept Medicare cuts if the Republicans would be willing to increase revenues.

If the Republican Party were a normal party, it would take advantage of this amazing moment. It is being offered the deal of the century: trillions of dollars in spending cuts in exchange for a few hundred billion dollars of revenue increases.