BOSTON (CBS) – It’s a happy day for the White House, no question.

A struggling incumbent who had been derided as impotent in recent months has just had his signature legislative accomplishment affirmed.

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President Obama can – and will – continue to boast about the benefits voters are already enjoying from the Affordable Care Act (ACA) and those yet to kick in.

But my guess is they’re not unhappy over at Romney headquarters.

As the day unfolds, watch for the following Republican themes: the ACA is now the “job-killing Obama tax hike,” and its affirmation is yet another example of that great conservative demon, “an imperial judiciary.”

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There’s a reason why you rarely heard Democrats talking about the ACA over the past year or so.

It consistently draws majority opposition in the polls, with independents and other swing voters especially wary.

Now the controversy is catapulted back toward the top of the political agenda, energizing the Tea Party and other elements of the right who now have only one remaining line of defense against their legislative nemesis – Mitt Romney.

If this doesn’t warm them up to him, nothing will.

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Jon Keller