President Obama and the Democrats have been ambushed. They blindly walked into the political trap Republicans set for them on Medicare.

Democratic strategists were certain that, with Paul Ryan on the Republican ticket, Medicare had become a better issue than ever for them. How do we know this? Democrats said so.

Ryan is the author of a Medicare reform plan that Democrats insist would “end Medicare as we know it.” That’s their mantra. Mitt Romney, who picked Ryan as his vice presidential running mate last week, has a similar plan of his own.

It didn’t occur to Democrats that Republicans might have devised, tested, and were ready to deliver a response that would put Democrats on the defensive. It’s a double whammy in which Obama and Democrats are held responsible for cutting Medicare spending and using the money to pay for the president’s unpopular health care plan, Obamacare.

Moving quickly, the Romney campaign packaged that two-step response into a crisp, 30-second TV ad that began being aired yesterday.  The campaign plans a large buy with the ad, particularly in swing states.

“You paid into Medicare for years,” the voiceover says.  (A picture of an elderly man is on the screen.)  “Every paycheck. Now when you need it, Obama has cut $716 billion from Medicare.  Why?  To pay for Obamacare.  So now the money you paid for your guaranteed health care is going to a massive new government program that’s not for you.”

The National Republican Congressional Committee, the campaign arm of House Republicans, developed this response to Medicare attacks. It consists of this: defend and attack. First, defend the Republican plan to reform and save Medicare, then immediately go on the attack, citing the Medicare funds used to pay for Obamacare.

The Republican strategy was tested in a special House election in Nevada in 2011. First, it had to be clear that Democratic candidate Kate Marshall, the state treasurer, would not vote to repeal Obamacare. She said she wouldn’t. Instead, in a TV spot, she zinged Republican Mark Amodei for proposing “to end Medicare as we know it.”

Amodei answered with an ad accusing Marshall of wanting to cut $500 billion from Medicare. His mother appeared in the ad, asking her son to block the cut. “You’d better, son, I’m counting on you,” she says.

Marshall came back with a second ad, this one simply saying Amodei would “end Medicare.” His mother showed up again in his response, and Amodei was cast as “the one candidate working to protect Medicare.”

The ads transformed the public’s perception of Amodei from a critic of Medicare to a supporter.  This occurred among all age groups. 

The strategy was designed merely to achieve a draw on the Medicare issue. But it did far better than that. Amodei won with 63 percent of the vote. The seat is now regarded as solidly Republican.

Now the NRCC has produced a 10-minute video that spells out how the strategy played out in Nevada. The video has distributed to Republican candidates. It urges them to “fully engage and lean into this fight” over Medicare.

Ryan, in an interview yesterday with Brit Hume of Fox News, said Medicare can be a winning issue for Republicans. “Absolutely, because we’re the ones who are offering a plan to save Medicare, to protect Medicare, to strengthen Medicare,” Ryan said. “We’re the ones who are not raiding Medicare to pay for Obamacare.”

Obama, he said, “is actually damaging Medicare for current seniors. It’s irrefutable and that’s why I think this is a debate we want to have and that’s the debate we’re going to win.”

Romney has promised to repeal Obamacare. By doing so, the money taken from Medicare would be returned. His reform of Medicare would give seniors a set amount each to buy health insurance from among competing options. Seniors could even choose to buy traditional Medicare if they wished.