Listlessness is bad politics. Defensiveness is poor strategy. And resignation is never inspiring.

You can feel elements of all three descending around President Obama as he fends off attack after attack from his conservative foes, who vary the subject depending on the day, the circumstance and the opportunity. This sense of drift inspired an explosion over the weekend of disparaging commentary (some of it coming, usually anonymously, from Democrats) about the president’s political infirmities.

Obama and his party are in danger of allowing the Republicans to set the terms of the 2014 elections, just as they did four years ago. The fog of nasty and depressing advertising threatens to reduce the electorate to a hard core of older, conservative voters eager to hand the president a blistering defeat.

American politics has been shaken by two recent events that hurt first the Republicans and then the Democrats. Republicans have recovered from their blow. Democrats have not.

Last fall’s government shutdown cratered the GOP’s standing with the public and confirmed everything Democrats had been saying about a House majority in thrall to a far right uninterested in governing. Then the Obama administration threw its adversaries a lifeline with the disasters that befell HealthCare.gov, empowering Republicans to remount their favorite hobbyhorse. House Speaker John Boehner used the foolishness of the shutdown to insist that there would be no more tea party adventures this year, no matter what Ted Cruz said.

And Republicans have broadened the assault whenever possible. Shamefully but effectively, many of them made Obama, not Vladimir Putin, the prime culprit in Putin’s invasion of Crimea, hanging the word “weak” around the president’s neck. Democrats thought the killing of Osama bin Laden would forever guard Obama from comparisons with Jimmy Carter. They did not reckon with the GOP’s determination to Carterize and McGovernize any Democrat who comes along.

Despite the large strides in the health-care Web site’s performance and despite Obama’s efforts to regain the initiative with executive action, Republicans remain on offense. Executive actions — even helpful ones like last week’s aimed at keeping workers from losing overtime pay by being falsely reclassified as supervisory — cannot transform the political agenda or mobilize a movement.

The most telling fact about the Democrats’ defeat in Florida’s special House election last week was the party’s failure to get its voters to the polls. This owed to many factors, but one of them is disaffection in Democratic ranks.

The recent NBC News/Wall Street Journal poll pegged Obama’s approval rating at 41 percent, his disapproval at 54 percent. But the most disturbing finding to him ought to have been the 20 percent disapproval he registered among Democrats. Winning back three-quarters of those discontented Democrats would, all by itself, bump up his overall approval rating by more than six points. It’s where he needs to start.

With more than two and a half years left in his term, Obama has already begun to convey a sense of resignation that his largest achievements (except, perhaps, for immigration reform) are behind him. His cool composure disinclines him to expressions of anger over how conservatives are foiling progress on job creation, education, the minimum wage and infrastructure investment. And the difficulty of getting anything through the House and past Republican filibusters in the Senate is limiting the Democrats’ policy imagination.

Going on offense means, first, building on what Senate Majority Leader Harry Reid is undertaking in his campaign against the Koch brothers and other right-wing millionaires trying to buy themselves a Congress.

This is not just a tactical effort to turn tens of millions of dollars in negative advertising into a boomerang by encouraging voters to ask why the ads are appearing in the first place. It is also about drawing a sharp line between the interests and policy goals of those fronting that money and the rest of us. And by the way, Republicans denouncing Reid were perfectly happy back in the day to condemn George Soros for his spending on behalf of liberals.

It also means embracing the Affordable Care Act, promising to keep it and improve it, and laying out what repeal would actually mean: to seniors enjoying additional prescription-drug benefits, to consumers protected from losing insurance because of preexisting conditions, to adult children now on their parents’ health plans. It means counting the cost of what state-level Republicans are doing in blocking 4 million to 5 million needy people from the Medicaid expansion.

Above all, it means lifting the debate from the hopelessness and exhaustion that are turning millions of Americans away from political engagement. The hope-and-change guy needs to have one more act in him.

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