Could Bob Casey actually lose this thing?

It doesn’t happen often, but every veteran political operative can tell you a few stories of heavily-favored candidates who lost because they took their opponents lightly and did too little.

I wouldn’t necessarily say that describes incumbent Pennsylvania Democratic U.S. Senator Bob Casey in his current re-election campaign, but it has been a low-energy affair in which his opponent, conservative Republican Tom Smith has steadily gained in polls. Smith now trails by only two percent according to a new Muhlenberg College survey.

UPDATE: A new Quinnipiac poll confirms the race has tightened. It gives Casey a 48-45 lead. Details here.

Another survey based on automated telephone interviews by Public Policy Polling showed Casey with an 11-point spread, 50 to 39 percent.

Smith hasn’t made his gains with charisma or a barnstorming campaign of voter engagement. He’s done it mostly by writing checks, though campaign manager Jim Conroy says Smith has been actively campaigning through the state.

Smith is a self-made millionaire who’s funded his own campaign to the tune of $16 million and counting. That bought a lot of TV time, and when Casey wasn’t advertising, it was inevitable that Smith’s numbers would move in a positive direction.

And if Casey hasn’t been doing his best to raise the profile of the campaign, can you blame him? If nobody knows who your opponent is, or is even sure if there’s an election, you don’t go around stirring things up. And as one of his campaign officials told me last week, the race has drawn so little media interest that if he were holding news conferences all over, they’d probably be ignored.

What Casey was doing was saving his campaign cash for October, so now he’s got the money to start whacking Smith the way Smith has been whacking him on TV, and maybe that will stem the Smith campaign’s momentum.

Meanwhile, it’s been a campaign without a single debate. Now that we’re watching, it’s about time for that, no?