Settle down, Pig Virus.

HOWARD BEACH, N.Y. — The Democratic Party’s rare loss of a congressional seat in its urban heartland Tuesday, accompanied by a blowout defeat in a Nevada special election, marked the latest in a string of demoralizing setbacks that threatened to deepen the party’s crisis of confidence and raise concerns about President Barack Obama’s political fortunes.

In New York, Republican Bob Turner soundly defeated Democrat David Weprin in a House contest that — in the view of party leaders, at least — featured an anemic urban machine, distracted labor unions and disloyal voters. In Nevada, a consequential state for the president’s reelection strategy, Democrats suffered a runaway loss rooted in a weak showing in Reno’s Washoe County, a key bellwether. . .

“Let’s face it — it has been a tough summer for Democrats,” said Jack Quinn, a top lobbyist and former White House Counsel to President Clinton. “But I really do think that people are feeling better.”

“They didn’t get the House and say, ‘We want half a loaf.’ They’ve said, ‘we want the whole g——— oven,’” he argued. “It’s time for the president to really draw some hard lines here.”

Rep. Henry Waxman (D-Calif.), among the most senior House Democrats, sketched out those lines.

“The Republicans want us to repeal the 20th century, the New Deal, the Fair Deal, to turn us back to the robber barons running the country, and to eviscerate the environmental and other regulations to protect public health and safety,” said Waxman. “And to cut spending in ways that would be very harmful to people who rely on government.”