April was a cruel month to be an elder Democrat in the Senate.

Sen. Robert Byrd (D-W.Va.), the chamber’s longest-serving member in history, had to defend his right to continuing chairing the Senate Appropriations Committee. Sen. Frank Lautenberg (D-N.J.), the Senate’s second-oldest Democrat, learned that he would face a serious challenge in this November’s election from a sitting House Democrat nearly half his age.

At least 15 Senate Democrats raised the issue of Byrd’s physical abilities during a private meeting with party leaders after Byrd was hospitalized twice this year. Rep. Robert Andrews (D-N.J.) entered the Democratic primary criticizing the senator for not running a “vigorous” campaign.

On Tuesday he told The Hill: “It’s up to voters” to decide if Lautenberg is too old.

“I have declined to raise it because it’s a decision for the voters,” Andrews said. “But I do think it’s relevant that he has not been interacting with people. He has an obligation to do that.”

In a chamber where the average age is 63 and seniority is valued, being young can prove a disadvantage. Critics say senators come to view their seats as lifetime appointments and are nearly impossible to defeat in general elections, even when their health fails.

Lautenberg said he’s perfectly capable of handling his duties. He recalls hearing a similar concern about his age raised by a lanky New Jersey mayor, to which he responded by suggesting he would propose state legislation banning people taller than 6 feet from holding public office.

“I work late, I’m one of the last to leave here, I don’t tire and I still ski,” the senior New Jersey senator said this month. “I mean, how can you compare one to another? I’m different in many ways from people my age.”

Byrd seemed to answer his critics by showing up for an April 16 hearing looking fairly spry in a freshly pressed suit. He smiled broadly and told his critics to “Shut up!” Nevertheless, he entered the room in a wheelchair, spoke sparingly and trembled when he clutched papers.    

“Whether you are a senator of 47 years, 64 years or 90 years, you rely on your professional staff for advice, counsel and recommendations,” said Jesse Jacobs, Byrd’s spokesman. “But ultimately it is each individual senator who is the final decision-maker, and such is the case with Sen. Byrd.”

Although U.S. citizens must be at least 30 to run for the Senate — the qualification is 25 for the House — its youngest member, Republican John Sununu of New Hampshire, is 43. Of the 100 members, only nine senators are in their 40s, while 28 are in their 50s, 37 are in their 60s, 20 are in their 70s and five are in their 80s. Byrd is the lone nonagenarian.

If the whispers surrounding Byrd have quieted for now, the issue has not gone away. People such as Doug McKinney, chairman of the West Virginia Republican Party, and Philip Blumel, president of U.S. Term Limits, say senators like Byrd do the chamber a disservice by hanging onto power past their ability to wield it effectively.

“A lot of people are concerned he’s not quite with it and he’s outlived his usefulness,” McKinney said of Byrd. “And he’s typical. Look at Ted Stevens [R-Alaska] and his ‘Bridge to Nowhere.’ It’s Democrats and Republicans alike. These guys scratch each other’s backs and turn the Senate into an old boys’ club instead of the People’s House.”

Blumel said older politicians appeal to many voters because they exemplify success at a later stage in life. But he added that those who, like Byrd, have served for decades make the system seem undemocratic.

“The problem with being 90 and being in Congress, where seniority counts so much, is that it becomes nearly impossible to defeat that politician and there’s no regular, competitive elections anymore,” he said. “People have less opportunity to weigh in on who represents them and participate in the process. And over a long period of time, the support of special interests becomes automatic with seniority and you end up with someone who can’t be beaten and represents a gaggle of those interests.”

Other elderly senators are frank that it is more difficult to be a senator in 2008 than it was decades earlier. Sen. John Warner (R-Va.), who is 81 and retiring, remembers only a few hundred letters coming into his office when he first became a senator in 1979.

“Now there’s up to 12,000 e-mails a week sometimes,” Warner said. “It’s become more and more demanding. The world has become a more complicated place in the 30 years I’ve been here. Things have changed.”

To be sure, Republicans have gone after their veterans in the past as well. In November 1998, the conservative magazine National Review ran an article urging then-Sen. Strom Thurmond (R-S.C.) to resign for the good of the Republican Party.

Thurmond, 95 at the time, promptly scribbled a Byrd-like response to his chief of staff, Duke Short: “Tell them to go to hell.” The magazine now hangs on Short’s living-room wall in Alexandria, where he has just finished a book on Thurmond.

“I can understand why people say it,” Short said of the criticism facing elderly senators. “But people get old at different ages. Some get old at 60. Some get old at 90. It’s all relative.

“I remember I was at a banquet one night when the senator was in his 80s and he was dancing out on the floor, and a woman came up to me and said, ‘Look at that. My husband is only 60 but barely wants to move.’ ”

Stevens is the chamber’s second-oldest member and is among those who say age isn’t as relevant as physical ability. He pointed to former Sens. Theodore Green of Rhode Island, who served into his 90s, and Carl Hayden of Arizona, whose House and Senate service from 1912 to 1969 give him the record for longest-serving member of Congress.

“Those guys had lots of mileage,” Stevens said. “I’m only 84. I exercise every day. I play tennis. I walk long distances. Age is an attitude, that’s all.”