The liberal group MoveOn.org is warning its supporters not to take a Barack Obama victory for granted this fall.

The anti-Iraq war group voiced concerns in a video sent to its members Tuesday that progressive activists may turn lethargic if they view as a given a victory by the likely Democratic presidential nominee.

“Obama is a terrific candidate and Republicans have definitely made a mess of things. But the truth is Obama also faces some real hurdles between now and November,” Pariser said.

“We can win, but we're gonna have to fight for every vote.”

The Illinois Democrat only has a three-point lead in national polls, said Pariser, who told supporters the race could turn and that anything can happen to a mid-summer lead. He cited Democratic presidential nominee Sen. John Kerry’s (Mass.) mid-summer lead in 2004.

Pariser listed a number of potential pitfalls for Obama that should encourage his supporters to work hard for a win.

He said GOP presidential candidate Sen. John McCain (Ariz.) can sway opinion with negative ads, and also claimed McCain has more cash on hand than Obama.

Obama has raised more money than McCain and appears to maintain an advantage in cash, but Pariser could be referring to the cash advantage the Republican National Committee has over its Democratic counterpart. When the figures are combined, McCain has a slight advantage, and the GOP funds could also be used against Obama.

Also, because McCain has decided to accept public matching funds, he has to spend all of the money he has raised for the primaries before the Republican convention.

Pariser also said the public doesn’t realize what McCain’s positions are on some issues. Pariser specifically said some believe McCain favors abortion rights.