As we head into some of Mitt Romney's most important weeks of the campaign — his choice of a running mate and his convention — it's worth taking a snapshot of the race today. The preponderance of evidence — polling and gut feel — tells me that President Obama has strengthened his position in the race.

My evidence? Polling in swing states favors Obama so far, and he has more plausible ways to 271 electoral votes than Romney. Moreover, recent national polls, such as CNN/ORC, show Obama above the magic 50 percent margin and with a lead outside the margin of error.

While still precarious, the economy is showing some rumblings of recovery. The housing market really does look as if it has hit a real bottom, after hitting some false ones, and it is beginning to recover. Exports are up sharply and a downward trend in the number of people seeking unemployment is accelerating. Perhaps, if an economic dawn is finally breaking, it will come too late for Obama, as it did for George H.W. Bush in 1992, but it can't hurt.

There are two basic reasons the race has shifted slightly in Obama's favor: 1. The president's campaign has won the battle of the negatives so far, casting serious doubts on Romney's commitment to the middle class; and 2. Romney has been a passive and ineffectual candidate.

Romney has time to overcome all this, and he will have the money to do so.  But he needs to get busy. He must have a running-mate choice and a convention that give him a bounce back to an even race, or a slight lead. If not, he will surrender control of the race.