Barack Obama's public approval rating has fallen faster than presidents from George W. Bush to Jimmy Carter, based on a RealClearPolitics review of historical Gallup polling.

Until Obama, Carter was the last president to begin his term in the high 60s. Carter first polled at a 66 percent approval rating. He did not reach Obama's present territory until mid September, when he hit 54 percent.  Carter fell lower in late October--51 percent. And that fall occurred after the Carter administration was branded with scandal, following the Bert Lance affair.

Gallup reports today that Obama has a 52 percent public approval rating, a new low. Yesterday's three-day Gallup average was 53. The day before, 54. Feels like a slow bleed is underway. Obama may soon recover. Presidents do. But these are bad numbers by historical standards.

Obama began his presidency at 68. He hit 69 the following day. That means he's dropped 16 points since day one.

So in less time than Carter, Obama has fallen more.

And Obama's bad numbers are fairly uniform. In the past day alone, NBC News/Wall Street Journal and the Pew Research Center have shown similar results.

Both W. Bush and Bill Clinton reached the low 50s sooner than Obama. W. Bush hit 53 in March; Clinton hit 51 within a month of his inauguration. But W. Bush and Clinton began their presidencies with approval ratings about 10 points lower than Obama. And indeed, Obama has therefore fallen faster than W. Bush as well.

Clinton's presidency was going far worse than Obama's at this point; Clinton hit 37 by early June 1993. George H.W. Bush also began low, at 51. But he did not return to that floor until October 1990, at 53 percent--more than a year after Obama.

Ronald Reagan began his presidency low as well, at 51. He too did not return to that low until after Obama, in mid September (it's worth noting that over that period Reagan was boosted by the assassination attempt).

In other words, Obama's got problems. Health care reform has come up against the rocks and the cop and prof race debacle has also likely taken some toll. Then there is the unemployment rate, almost assured to soon reach double digits.

Richard Nixon was in office more than a year before reaching the low 50s. Lyndon Johnson did not fall that low for several years. Others like John F. Kennedy floated far higher for his 1000 days. And Dwight Eisenhower did not hit the low 50s until 1958.

In the end, approval rating also concerns symbolism. Once a president falls below 50 percent he can no longer say he has the majority of the public behind him--a knockdown blow for a president's legislative ambitions.