Does Obama Lack a Political Identity?

The power shift in the senate following last night's victory by Republican Scott Brown in Massachusetts comes on President Barack Obama's first anniversary in the White House. His job approval has fallen to 50 percent. CBS News senior political correspondent Jeff Greenfield looks at what's behind his falling numbers.

Just a year ago, 21 guns were commemorating Barack Obama's improbable ascension to the presidency. Today, the White House is taking heavy incoming political fire. Special Report: Obama's First Year

What's happened? The roots may lie in his favorite campaign theme: "Yes we can!"

The question is: Yes he can…what?

Princeton University's Julian Zelizer echoes a growing criticism: that Americans don't know what Mr. Obama stands for.

"I don't think Obama has a message yet," Zelizer said "I think he is an elusive figure and a figure that has not defined himself politically."

And that elusiveness is especially harmful in a time of economic insecurity.

If Americans were asked, in Ronald Regan's famous phrase, "Are you better off than you were a year ago?" - few would answer yes.

Not coincidently, nearly half of Americans think President Obama has done too much for banks; more than half say he's done too little for the middle class.

Moreover, the very trait that served him well during the campaign - a cool, calm demeanor - may be cutting against him now. To put it another way: "Who's afraid of Barack Obama?

"The only way for a President to move forward is to be willing to use the hammer, so to speak, to get people to vote his way," Zeziler said.

There's another cloud on the President's horizon. Last night's Massachusetts Senate result is going to energize Republicans nationwide. Seats that once looked safe for Democrats are now likely to be more contested, draining resources away from tougher battles.

Greenfield spoke with "Evening News" Anchor Katie Couric Wednesday night

Couric: And Jeff, what do you think the president's biggest mistake was in year one?

Greenfield: Whatever he did was going to come with high costs, because we were near an economic calamity. If you talk to progressives in the Democratic party, they'll say he put too many people in economic positions of power who were responsible for the meltdown in the first place - wasn't tough enough. A wider swath of people say you know with the economy and jobs so central in the American focus, the health care focus of Obama may have been off the point.

Couric: Now that they can, do the Republicans filibuster at their own peril?

Greenfield: We have not seen any political price they've paid for lockstep opposition to the president. It's the dog that, so far, has not barked in the night.