Presidents can't pass laws on their own. That's why I've long argued Obama deserves more credit for his many legislative accomplishments. But presidents can run enforce laws on their own--or, at least, without nearly the same constraints on their power. And in one key policy area, antitrust policy, President Obama doesn't seem to be doing as much as he could, according to a Washington Post story by Jia Yin Lang:

The Justice Department's antitrust division has yet to exercise its signature power: to bring a case against a corporate titan suspected of abusing its dominance. In its other central role, as a merger cop, the division challenged in court fewer than half as many deals in 2009 as the Bush administration did in its last year in office, though the number of mergers also declined by about half.
Instead, federal antitrust lawyers have eschewed aggressive litigation against big business in favor of a less-risky approach that works with companies to resolve anti-competitive concerns, according to many antitrust experts.
"They're running a good shop. It's just not markedly different," said Albert A. Foer, president of the American Antitrust Institute, a research and advocacy group. "Anybody that wants to argue the Obama administration is anti-business or socializing America is not going to find much evidence in the antitrust division."

I trust Foer on this, and not just because his son happens to be my boss. He's a well-known, highly respected authority on antitrust issues. If he's disappointed with the administration's performance, you should be, too.