Updated

"If Obamacare is not deemed constitutional, then the first three and a half years of this president's term will have been wasted on something that has not helped the American people."

-- Mitt Romney campaigning in Salem, Va.

While conservatives would surely send up a cheer if the Supreme Court were to strike down President Obama’s 2010 health law on Thursday, moderate Democrats would certainly have to stifle some shouts of their own.

As President Obama grinds forward in a political version of trench warfare – constantly shoring up his lines and then trying to make incremental progress – a growing number of moderate Democrats, especially from red states, are going AWOL.

President George W. Bush saw this phenomenon in 2004 when moderate Republicans from Blue States started putting some daylight between themselves and the embattled leader of their party.

More On This...

But what’s happening to Obama has extra sting, especially since it’s happening so soon.

On Tuesday, Sen. Claire McCaskill, D-Mo., became the ninth sitting Democratic member of Congress or governor to declare that he or she would not be attending the Democratic National Convention on Labor Day weekend. Two Democratic House candidates have already made clear that they won’t be anywhere near Charlotte when the confetti cannons go boom.

This is unhappy news because it reinforces the storyline about a beleaguered Democratic convention. Democrats have already trimmed the schedule and lowered expectations for the event because of a host of problems, the chief one being that the state looks increasingly out of play for Obama.

But there are other woes, too. Unions aren’t happy about bankrolling a convention in a right-to-work state. Same-sex marriage enthusiasts aren’t happy to be celebrating their pro-gay marriage president in a state that explicitly forbids the practice. North Carolina Democrats are in disarray on the state level.

What was once supposed to be evidence of Obama’s appeal beyond the traditional Democratic base is now annoying to the Democratic base on which the president is leaning in hopes of winning a narrow re-election.

Now, the Democrats from the Clinton wing of the party are jumping off too. It makes sense. As the president continues to cater to the liberal base of his party – temporary amnesty and work visas for certain illegal immigrants, the gay marriage evolution, the repeated calls for higher taxes on top earners, the attacks on Mitt Romney’s record as a CEO, etc. – the clear message to the moderate minority of Democrats is that they are on their own this fall.

This reflects something we’ve seen throughout the Obama presidency. When the president looks like he is about to move to the middle, such as appointing a new chief of staff from the Clintonian, corporate wing of his party or opening a dialogue about streamlining the corporate tax code, he never makes it stick.

This then causes the president to have to go back and reassure his base, and then disappoint and further alienate moderates yet again. Charlotte is this in microcosm.

The list of Democrats distancing themselves from Obama will increase in direct correlation to Romney’s performance in the polls. The better Romney is doing in a state, the more incentive there will be for Democrats to get away from the president.

And unlike 2004, where a more disciplined Republican Party was still capable of knocking heads together when members got too sassy about Bush, there seems to be no consequence so far for Democrats who go rogue. Except for Corey Booker’s hostage video, there have been no appreciable consequences for the moderate Democrats who spout off about their differences with the president.

Imagine, then, what would happen on Thursday if the Supreme Court were to give Obama’s health law a big thumbs up? The law remains unpopular, especially in red states like McCaskill’s Missouri and swing states like Pennsylvania and Virginia. What is a Democrat running statewide in such a place to do? Certainly not join the White House in exalting the law and its requirement to purchase insurance.

The pending court decision has kept the discussion frozen. But once there is certainty, the political consequences will come in a torrent.

One thing these moderate Dems share with the president is an aversion to the idea of the high court allowing the law to stand, but carving out the compulsory insurance provision that finances the new entitlement program at the heart of the law.

If the mandate is gone, the left will be screaming for a government-run insurance program or a European-style, single-payer program to replace it. Moderates will have to sprint far away from those ideas as fast as possible.

But if the court were to simply demolish the law, now there is good news for moderate Democrats. Even those who voted for it under duress could express some measure of relief. The final product just didn’t pan out as they had hoped, they could say.

This also eliminates a wonderful talking point for Republicans and gives Democrats the chance to do what the red team is currently doing on health care issues: puff out vague expressions and buzz words.

If the court gives Obama’s health law the heave ho on Thursday, there will be plenty of moderate Democrats stifling smiles.

Poll Check: About Bain

The latest Wall Street Journal/NBC News poll shows the presidential race still a statistical dead heat between Barack Obama and Mitt Romney among registered voters, with Obama at 47 percent and Romney at 44 percent.

One nugget you might have missed, though:

The number of voters saying what they’ve seen or heard about Romney’s business career makes them feel more negative is up 6 points from January to 28 percent. This is not surprising given the tens of millions of dollars that have been spent between the Republican primaries and ongoing attacks from Obama and his allies.

But the percent of voters who said they feel more positive about what they’ve seen and heard about Romney as CEO? Up 7 points to 23 percent.

Obama should remember: When he whacks Romney on Bain Capital, he is actually introducing many voters to a previously unknown biographical point that many will like.

We’ll be getting some more data on issues tonight, when the latest FOX News poll is unveiled on “Special Report with Bret Baier” at 6 pm EDT. On tap tonight: voter attitudes on health care and immigration.

Poll Check: Swing State Boost for Obama  

Quinnipiac University polls of Ohio, Florida and Pennsylvania show just how tough Mitt Romney’s task really is.

Romney must win both Ohio and Florida to unseat President Obama, and the polls show a tough task ahead in the Buckeye State. Obama leads Romney 47 percent to 38 percent, Romney’s worst showing since the school started this cycle’s polling there in February.

If there’s any state in the nation where attacks on Romney’s time as a CEO could work it’s Ohio, with high union membership, hard feelings about off shoring of jobs and a large percentage of lower middle class voters. Notable too is the 15-point deficit Romney is carrying with female voters.

Florida remains essentially unchanged with Romney trailing Obama by a thin 4 points. The race there promises to be a pitched battle.

Pennsylvania, essentially a must win for Obama, remains something of surprise this cycle. Romney is faring better in this traditionally Democratic state than many expected. He trails the president by 6 points, 39 percent to 45 percent. But happily for Romney, the pool of undecided voters is large: 10 percent overall and 10 points among independents, with whom Romney already leads.

When you hear that President Obama will take his post Independence Day campaign swing through Western Pennsylvania, it’s certainly no coincidence.

And Now, A Word From Charles

“I am deserting [President Obama]. I will not be in Charlotte. Surprise.

And I think the reason they're scaling back from the extravaganza and the pomp of, what was it, in Colorado in 2008, is not because of any diminution in Obama's self-regard.  It's because they're running out of money. I think they also understand there will be very little interest when you re-coronate a president.”

-- Charles Krauthammer on “Special Report with Bret Baier.”

Chris Stirewalt is digital politics editor for Fox News, and his POWER PLAY column appears Monday-Friday on FoxNews.com. Catch Chris Live online daily at 11:30amET  at  http:live.foxnews.com.