A choice or a referendum? With Mitt Romney emerging as the likely Republican nominee, that is the question on which voters can now start focusing. And a new ABC/Washington Post poll shows how crucial their answers will be.

If the election is framed as a judgment on Obama’s record – if voters ask, “Am I better off than I was four years ago?” – the advantage clearly rests with Romney. Only one in 10 Americans rates the state of the union as good, and only three in 10 say the country is headed in the right direction. On every question concerning his handling of the economy, the president’s rating remains below 50 percent.

But the picture changes dramatically when voters compare Obama to Romney. In a head-to-head matchup, the Democrat leads the Republican 51 percent to 46 percent. Asked who better understands the economic problems facing Americans, voters prefer Obama by 17 points. His margins are similar on handling of terrorism and foreign policy. If Americans think of the election as a choice between two specific alternatives, Obama becomes the favorite.

Romney’s strongest bet remains the weak economy. Unemployment has dipped to 8.3 percent, but that’s still devastatingly high for many families, and the real jobless rate – including discouraged job seekers and part-time workers – is about 15 percent.