Here is an article from the Boston Herald on Kerry being AWOL from the Senate:

Presidential hopeful John F. Kerry has been a virtual no-show in the U.S. Senate over the past 14 months, but he hasn't missed a paycheck, even though a dusty federal law says some of his $158,000 salary should have been withheld.

During his run for the presidency, Kerry has missed every one of the 22 roll call votes in the Senate this year and was absent for 292, or 64 percent of the roll call votes last year, according to a Herald review of Senate records.

That means the Massachusetts senator has been away from his post in the Senate chamber for at least 128 days over the past 14 months.
...
Section 39 of the United States Code Service requires the Secretary of the Senate and the Chief Administrative Officer of the House to deduct daily pay from members for each day they are absent.

The only legal excuse is if the senator or representative, or one of their family members, is ill, the law states.

But do you think that Kerry (one of the wealthiest members of the Senate) will actually cut a check to the US Treasury? I doubt it. More importantly is the fact that the people of his state are not being represented. What kind of President would he be based on the fact that he is not even representing the people of his state, which he took an oath to do? At least Bob Dole resigned from the Senate when he ran in 1996 so that the Governer of Kansas could appoint a new Senator to represent the people of that state. Kerry should do the right thing and resign... but he's probably too afraid he'd lose and then be out of a job all together.