The tidal wave of anti-debt, anti-big-government voters that swamped Democrats in the 2010 congressional elections is readying itself again, poised to sweep Mitt Romney into the Oval Office, some political observers say. “It’s very, very likely,” veteran Republican campaign pollster John McLaughlin said, predicting a Romney tsunami Tuesday. “Romney has surged in all the target states,” Mr. McLaughlin said. “The undecided vote is not really undecided. They overwhelmingly disapprove of the job the president has done and will largely vote against the incumbent. It’s a hidden vote that will vote against the president.”