The Gallup Poll daily tracking indicates McCain leads Obama 46 percent to 45 percent in a hypothetical general election matchup, while Clinton leads McCain 48 percent to 44 percent.

The results are based on May 22-25 and May 27 Gallup Poll numbers. The combined data from 4,411 registered voters has a sampling error of plus or minus 2 percentage points.

In the race for the Democratic presidential nomination, Obama has a six-point lead over Clinton, 50 percent to 44 percent, Gallup figures from May 24-25 and May 27 show.

Gallup said Obama's lead has been as high as 16 points in the last two weeks, but Clinton has fared better in recent days.

The numbers are based on a sample of 1,270 Democratic and Democratic-leaning voters. The poll has a margin of error of plus or minus 3 percentage points.