During the 2008 campaign, President Obama promised to deal with one of the world’s great scourges — thousands of nuclear weapons still in the American and Russian arsenals. He said he would resume arms-control negotiations — the sort that former President George W Bush disdained — and seek deep cuts in pursuit of an eventual nuclear-free world. There is no time to waste.

In less than nine months, the 1991 Start I treaty expires. It contains the basic rules of verification that give both Moscow and Washington the confidence that they know the size and location of the other’s nuclear forces.

When Obama meets Russia’s president, Dmitri Med-vedev, in London on April 1, the two should commit to begin talks immediately and give their negotiators a deadline for finishing up before Dec. 5. For that to happen, the Senate must quickly confirm Obama’s negotiator, Rose Gottemoeller, so she can start work.

Obama and Medvedev should also pledge that these negotiations are just a down payment on a more ambitious effort to reduce their arsenals and rid the world of nuclear weapons. The next round should aim to bring Britain, France and China into the discussions. In time, they will have to cajole and wrestle India, Pakistan and Israel to the table as well.