At Roll Call, an Uneasy Silence

"Every senator plays a unique role within the process; all 100 fit a specific place," says Jay Truitt, vice president of government affairs for the National Cattlemen's Beef Association. He relies on Johnson to advocate for his industry. Yet he also knows he can count on others in the meantime. "While one single senator has a great deal of power, they're not bigger than the process. . . . We are going to do an appropriations bill. . . . The work will go on."

"There isn't an event that goes on around here where Tim isn't mentioned and prayers aren't offered," says Sen. John Thune, the Republican from South Dakota.

Thune lost his first race for the Senate to Johnson in 2002 by 524 votes. When the Republican visited Barbara Johnson after her husband was stricken, she noted that her husband is a tough fighter. Thune, recalling that contentious election, said wryly, "Believe me, I know it!"

Expressing both qualities of senatorial absence, Julianne Fisher, Johnson's communications director, finds herself issuing somewhat paradoxical messages: "The office is open and we continue to work." And: "The senator is not replaceable."

Her predicament is obvious. To suggest the work has been seriously disrupted would be to imply the people aren't being served. To say everything is being accomplished too well would imply the senator is superfluous.

Of course, senators might be absent for many reasons.

Some run for president. In 1996, Majority Leader Robert Dole resigned his seat to campaign against President Clinton. This year, with at least a half-dozen Democratic and Republican senators already vying for 2008 -- and none publicly planning to give up his or her seat -- absenteeism is certain to rise. Phoning in votes from New Hampshire or Iowa is not allowed.

Sometimes senators aren't very active even when they are present. By the time he was 98, in 2001, an exceedingly frail Strom Thurmond of South Carolina rarely participated in debates, gave speeches or interviews, questioned witnesses, wielded a gavel or introduced consequential bills.

Karl Mundt, a Republican from South Dakota, suffered a stroke in 1969, but held his seat until the end of his term in January 1973, even though he could no longer report to the Senate. Johnson holds Mundt's old seat.

In 1988, Joe Biden of Delaware was out for seven months recovering from two brain aneurysms. He proves a senator can bounce back from brain surgery, get reelected and run for president.

Something Was Wrong

The recording of the moment when Johnson slipped from present to absent is chilling to hear.

He was in a basement studio in the Capitol for his weekly conference call with South Dakota reporters. There was one last question about funding for four projects, including a medical school and a Boys and Girls Club.