Even

It is convention eve, and the latest Gallup tracking poll shows the presidential race as a tie.

PRINCETON, NJ -- The latest Gallup Poll Daily tracking update finds a precise tie between John McCain and Barack Obama, with 45% of nationwide registered voters currently supporting each candidate for president.

The initial polling results on Joe Biden show very little impact.

Barack Obama's selection of U.S. Sen. and former presidential candidate Joe Biden as his running mate is not generating a momentous immediate reaction from the nation's voters. Just 14% of registered voters interviewed in a new USA Today/Gallup poll say Biden makes them more likely to vote for Obama in November and 7% say less likely while 72% say he will not have much effect on their vote.

And while Democrats continue to have a 10% advantage in registration, Barack continues to struggle to get Democrats to support him.

Whereas 84% of Republicans polled from Aug. 11-17 say they will vote for McCain in November, only 79% of Democrats say they will vote for Obama. A similar gap in party loyalty has been seen each week since Obama clinched the Democratic nomination in early June. Over this period, Obama's Democratic support has ranged from 78% to 82% while McCain's Republican support has ranged from 83% to 85%.