Sedalia, Mo. ? It’s 7:19 p.m., yet Rep. Ike Skelton appears hard at work. “I just voted against the repeal of DADT,” Skelton tweets via BlackBerry to alert a few hundred followers to his stance against gays openly serving in the military.

This from a man who doesn’t have a personal computer in his office and displays photos of himself with former President Harry Truman.

Now at age 78, after more than three decades in Congress, Skelton is going modern.

Facing what may be the most difficult election of his long career, the Democrat from rural Missouri has embraced Twitter, Facebook and YouTube. He’s amassing thousands of e-mail addresses. And he has hired a cadre of consultants to manage his message, raise money and dig up political dirt for a campaign blitz that is about four times larger than anything Skelton’s ever done, according to a longtime adviser.

With an electorate that appears hostile to the established political order, many longtime members of Congress accustomed to cruise-control campaigns have had to make a choice for this year’s midterm elections: get modern or get out.

Wisconsin Democrat David Obey, the third-longest serving current House member, announced last month that he was retiring. Michigan Republican Vern Ehlers opted for retirement instead of a 10th congressional campaign. Sens. Kit Bond of Missouri, George Voinovich of Ohio and Jim Bunning of Kentucky — all veteran lawmakers now in their 70s — also chose to retire.

Others are attempting to adapt by embracing technology that hadn’t even been imagined when they first were elected, hiring campaign staffs sooner than usual and stockpiling cash instead of giving it away to others.

Florida Republican Bill Young, 79, who has served in Congress half his life, is collecting online contributions for the first time. House Budget Committee Chairman John Spratt of South Carolina, first elected when Ronald Reagan was president, launched a new website and YouTube, Facebook and Flickr sites last fall.

But no one perhaps illustrates the transformation better than Skelton, the Democratic chairman of the House Armed Services Committee who since 1976 has routinely carried about two-thirds of the vote in a district that otherwise favors Republicans.

Skelton has prevailed by defending the district’s two military bases, backing conservative causes and having regular face-to-face meetings with constituents. He still shakes hands nearly every weekend at small-town diners and Boy Scout ceremonies, and makes sure to buy a pie at community fundraisers. Through Memorial Day, he had attended more than 100 local events. But behind the scenes, Skelton’s methods have undergone a makeover.

When he recently hosted his 22nd annual conference for would-be government contractors, Skelton slowly moved through the crowd chatting about people’s home towns and shared acquaintances.

“I’m a very hard-core conservative guy, but I like Ike Skelton,” said electrician Jim Stuck, among those on hand. “He’s old-school.”

Yet at that very moment, Skelton was doing a very new-school thing. From his Washington office nearly 900 miles away, a message shot across his Twitter and Facebook pages: “About to kickoff this year’s Procurement Conference in Sedalia — a day long meeting to spur small business growth throughout Missouri.”

Skelton didn’t write or dictate the words. Instead, a pair of 23-year-olds in his congressional office were speaking for him over the Internet.