Michael Barone devotes his latest column to a question President Obama has not satisfactorily answered to date: What would he do with another four years in office?

“One question, Mr. President,” read the words on the front cover of this week’s Economist, behind a silhouette of the back of Barack Obama’s head, “just what would you do with another four years?”

It’s a good question, and one that’s still open as Barack Obama prepares to deliver his acceptance speech at the Democratic National Convention in rainstorm-plagued Charlotte Thursday night.

Other presidents seeking reelection have usually provided a more or less convincing answer. George W. Bush said he would try to reform Social Security and advance energy independence.

Bill Clinton said he would provide “a bridge to the 21st century,” which turned out to include significant tax cuts and a lunge toward Medicare reform.

Bush failed to deliver on Social Security, and Clinton failed to deliver on Medicare, but both tried to pivot from a first-term to a second-term agenda. The first George Bush, in contrast, didn’t seem to pivot. He gave the impression he’d just keep going on. That wasn’t good enough for voters.

Obama similarly has not pivoted. Unlike Clinton, he did not shift ground when his party was rejected in the off-year election.

For a second term he has been calling for more infrastructure stimulus, more unionized teachers, and (though he has said it’s harmful in a time of economic sluggishness) higher tax rates on high earners.