Republican Rep. Bill Cassidy, challenging incumbent Democratic Sen. Mary Landrieu in Louisiana, is pushing just as hard. “Sen. Landrieu, I voted for you before, but when you voted for Obamacare, I knew I’d made a mistake,” says a woman in a Cassidy ad featuring Landrieu voters who say her support of the health care law turned them away from Democrats.

Joni Ernst, leading the Senate race in Iowa, is pushing hard on Obamacare, too. And in North Carolina, where Republican Thom Tillis is trying to catch up to incumbent Democratic Sen. Kay Hagan, Obamacare is not just a bad law leading to higher premiums, high deductibles and narrower choices of doctors — it’s also a window into Hagan’s character.

“Its importance is not only in the policy itself, but more so in the fact that Sen. Hagan said at least 24 times that ‘if you like your healthcare, you can keep it,'” says a Tillis campaign source.

So Republican candidates bash Obamacare and move up in the polls. Given that public opinion remains firmly against the healthcare law — as it has been for years — that’s not a shock. Democratic beliefs to the contrary are probably wishful thinking.