The mainstream/liberal/elite/establishment media could pool resources and hire a brand-management firm like Hill + Knowlton. It could put banners on I-95, I-80, I-30 and I-5. It could assign all of its foot soldiers to hit the airwaves and speak in flattering tones about mainstream mediaism.

But all those methods could never deliver the PR payoff that conservative media outlets are providing these days, through their investigative stories on Barack Obama. The inventory consists of the story about Obama’s relationship with “radical” Harvard University law professor Derrick Bell; the 10-part series on the “Obama you don’t know” in the Washington Examiner; and the amplification of Obama’s 2007 speech at Hampton University, courtesy of the Daily Caller.

As these tracts overpromise and underdeliver, they also send the public the message that maybe the media — not to mention Obama’s political opponents, especially those in the 2008 primary contest — took a decent look at his past. Perhaps the “vetting” that so many critics say never happened, happened.

There’s still time, of course, for more investigation of the president’s past associations and ideologies. Yet if the usual suspects claim to have something big on this front, click with caution.