President Obama's post-convention spike continues, and that's especially evident — and important — in the steady increase in his approval rating, which is at a 15-month high in the Gallup daily tracking poll.

Obama's approval rating in Gallup now stands at 52 percent — above the 50 percent mark that usually nearly ensures re-election. Moreover, his disapproval rating has dropped to just 42 percent.

Pre-convention, Obama's approval-to-disapproval rating stood at 45 percent to 48 percent. That means it has swung 13 points during and in the aftermath of the convention.

The last time Obama was at 52 percent was during the three-day period of May 23-25, 2011.

Obama's approval rating also jumped to the same 52 percent mark in Rasmussen's daily tracking poll, while 47 percent disapprove. That compares to a 48-52 approval-to-disapproval split the day the convention started.

It remains to be seen if Obama will see any swing downward from the tepid August jobs report. But for now, it's looking like the DNC was a lot more successful for its candidate than the RNC was for Mitt Romney.

Recall why the 50 percent threshold is important, per Gallup managing editor Jeffrey M. Jones:

The 50% approval mark is significant because post-World War II incumbent presidents who have been above 50% job approval on Election Day were easily re-elected. Presidents with approval ratings below 50% have more uncertain re-election prospects. Historically, two presidents below 50% in their final approval rating before the election -- George W. Bush and Harry Truman -- won, and three, Gerald Ford, Jimmy Carter, and George H.W. Bush, lost.

In 2004, Bush jumped above 50 percent around this time, too — he bumped up to 52 percent the Sept. 3-5, 2004, tracking period, and he stayed above 50 percent for the rest of the month.