Click here to watch "Passed Over."

The McCain camp is asking the same question that large numbers of Hillary Rodham Clinton supporters are asking -- why isn't she Barack Obama's VP? The campaign released "Passed Over" early Sunday -- 3 a.m., to be exact. Not coincidentally, this is the same time Obama sent a text message announcing Sen. Joseph Biden, D-Del., as his running mate. It also harks back to Clinton's infamous "3 a.m." ad on national security.

"She won millions of votes, but isn't on his ticket. Why?" an announcer chides. "For speaking the truth." The ad goes on to air footage of Clinton criticizing Obama on a number of points, including his involvement with convicted Chicago developer Tony Rezko, something a spot the campaign released last week scrutinized as well. The ad concludes by implying this criticism is why the Illinois senator didn't pick Clinton as his running mate: "The truth hurt. And Obama didn't like it."

The ad doesn't actually mention the words "passed over" and doesn't attempt to persuade Clinton supporters to vote for John McCain. Nonetheless, the spot capitalized on a touchy issue at an opportune time, right before the Democratic convention officially started today. By highlighting the divisive relationship between the two Democrats and the still-fresh political wounds millions of Clinton supporters may be feeling, the campaign is implicitly suggesting McCain is a better option for these voters than Obama.

What does Clinton think about the spot? She's not too pleased, according to this statement issued today by spokeswoman Kathleen Strand: "Hillary Clinton's support of Barack Obama is clear. She has said repeatedly that Barack Obama and she share a commitment to changing the direction of the country, getting us out of Iraq, and expanding access to health care. John McCain doesn't. It's interesting how those remarks didn't make it into his ad."