Hillary Clinton does not let her opponents up off the mat when they are down.  She is trying to make sure Samantha Power’s negative impact on Barack Obama lives on long after Power is gone from Obama’s campaign. In a campaign email blast Saturday, Clinton made the argument that Obama is prone to telling voters one thing, only to do or say something different in another context. The memo read, in part:

After months of speeches from Senator Obama promising a hard end date to the Iraq war, his top foreign policy adviser that counseled his campaign during that period is on the record saying that Senator Obama will “not rely on some plan that he’s crafted as a presidential candidate or a U.S. Senator.” Voters already have serious questions about whether Senator Obama is ready to be Commander-in-Chief. Now there are questions about whether he’s serious about the Iraq plan he’s discussed for the last year on the campaign trail. Senator Obama has made hard end dates about Iraq a centerpiece of his campaign and has repeatedly attacked Senator Clinton for not being clear about her intentions with regard to troop withdrawal. It turns out those attacks and speeches were just words. And if you can’t trust Senator Obama’s words, what’s left? This latest incident is part of a larger pattern where Senator Obama doesn’t deliver on the promises he makes on the campaign trail — whether it’s his 2004 Senate race or his 2008 White House campaign. In 2003, Senator Obama said he was for a single payer health system, but now opposes plans that cover every American. He promised to repeal the Patriot Act, but then voted to extend it. He promised to normalize relations with Cuba, but flip-flopped when he started running for president. In 2008, Senator Obama rails against NAFTA in Ohio while his top economic advisor assures the Canadians his rhetoric is just “political positioning.” He promises to opt in to public financing if the GOP nominee does, but then breaks that pledge in real time. He promises to withdraw from Iraq within 16 months, and now his top foreign policy adviser says that he’s not relying on the plan. With a short record to run on, Senator Obama’s entire campaign is based on the speeches he makes on the campaign trail. So when he and his advisers dismiss the plans he touts on the stump, it undermines his entire candidacy. Americans have heard plenty of speeches.

This, of course, is the latest twist on Clinton’s efforts to attack Obama’s rhetoric. First, she tried the “he’s all talk” tactic. Now she says “you can’t really trust the talk, so what is left?” (The corrollary point that he’s too inexperienced hardly has to be raised–once SNL does a bit like this, you know that point is sinking into the national psyche.) Hillary’s effort to attack the reliability of Obama’s rhetoric is now aided by increasingly tough media coverage on topics such as his evolving stance on Iraq.

On a broader level, all this suggests that Obama will have a difficult time getting off the defensive. Clinton will raise issue after issue of alleged inconsistency, forcing him into a tedious process of trying to rebut each alleged policy reversal. (Notice Clinton is more than happy to invoke McCain’s argument that Obama has reneged on his public financing pledge.) It reminds one of the Republican “flip flop” barrage aimed at John Kerry in 2004. Even liberal commmentators (h/t NRO)  are concerned that the impression created is “that Obama won’t fight back, that he’s easy to fluster, that he’s weak.”

What does Obama have on his side? Math. Wyoming was another comfortable win for him (although just a net gain of two delegates) and he leads in Mississippi. However, the Clinton line that Democrats should be concerned that he is not winning in must-win states for November is gaining traction. Will his delegate lead stand up after weeks of Clinton attacks (even with possible do-over elections in Florida and Michigan)? Probably. But the fact that she is still in the game and these questions are being raised indicates the “inevitable Obama” meme is likely a thing of the past. And even if he is still a dozen or so delegates ahead, but has lost Pennsylvania, Florida, and Michigan and is doing worse than Clinton in head-to-head match ups with McCain, will superdelegates care who’s marginally ahead? The answer is “no.”