David Brooks wants to know why the presidential race is as close as it is given that the economy stinks, President Obama is too far left for the country and he’s lost independent votes. Brooks attributes it to Obama’s “post-boomer leadership style.” Sigh. (Is “post-boomer leadership style” the pants crease of 2012?)

We offer a different question: Why is the race as close as it is given that Mitt Romney is supposed to be a stiff, he’s on the wrong side of history on gay marriage and Obama got Osama bin Laden? He was the damaged candidate, bruised after the primary, we were led to believe.

I go back to the fundamentals of the race. Each side has its base locked up, leaving that middle of the political spectrum up for grabs. Although “independents” are a greater share of the electorate, only about 7-10 percent of the electorate is really up for grabs. (The rest of the independents lean one way or the other.) There isn’t that much room for a big lead at this point in the race. And there won’t be — for a while.

Perhaps the race stays nip and tuck to the very end. But it is also quite possible that Obama has topped out in his support (at about 47 percent of the electorate). He has 100 percent name identification, and the results of his presidency ( a tepid economy, a huge debt, bin Laden dead but rising challenges to American power around the globe) are unlikely to change by Election Day. But Romney (political junkies may find it hard to believe) still is a question mark for many voters.

The New York Times-CBS poll shows a full 31 percent undecided or lacking enough information to form either a favorable or unfavorable opinion of Romney. In other words, Romney has room to grow.

And this is how presidential reelection races often go. Only over time do the less ideological, less attentive voters come to know the challenger. It was not until the 1992 Democratic National Convention and the bus tour that followed that Bill Clinton solidified his lead over President George H.W. Bush, in essence passing the “Is he presidential?” test.

In 1980 that point came in the debates. As Michael Barone recalls:

Most voters were ready for an alternative [to President Jimmy Carter] but were wary of Reagan, who was 69 years old and supposedly extreme conservative. He might have disqualified himself in a number of ways.

Instead, in his one debate with Carter, on the Thursday before the election, Reagan echoed a 1934 Franklin Roosevelt fireside chat, which he remembered but the press corps didn’t. “Are you better off than you were four years ago?” he asked voters.

Opinion moved quickly. Weekend polling showed an unprecedented 10 point shift from Carter to Reagan. Pollster Pat Caddell had to go to the White House Monday morning and tell Jimmy Carter that he was not going to be re-elected president of the United States.

In short, the answer to Brooks’s question — why isn’t Obama getting trounced? — is that it is too early to say. At some point Romney will either pass or fail the “Is he presidential?” test. (For Republican challengers, this generally entails reassuring suburban voters, coming off as responsible on foreign policy and having a domestic agenda that seems a plausible antidote to liberal governance.) If he does pass, then that 31 percent of the electorate that hasn’t quite figured him out will shift significantly his way and his top-line number will improve. If Romney can’t make it over that bar, Obama will win, in essence, by default.

For now, however, after nearly 3 1/2 years in office the president hasn’t won over a majority of the electorate. That’s problematic, especially since — the media keep telling us — Romney is a weak candidate. That must make Obama an enfeebled incumbent, with or without that “post-boomer leadership style.”