Despite vigorous affirmations by Sen. Jim Jeffords (Vt.) that he relishes a tough re-election battle next year and that his health is good, sources say the 70-year-old Independent will announce his retirement this afternoon.

Jeffords has been the center of rampant speculation that he would not seek a fourth term in 2006, but he and his office have done everything they can in recent months to tamp down such rumors.

Jeffords told Roll Call in February: “I feel good and healthy. I just got two new eyes; I feel better than I have in years.”

Nonetheless, Jeffords is set to tell his constituents at a 1 p.m. news conference in Burlington that he will leave the Senate when his term expires at the beginning of 2007, according to Washington, D.C., insiders.

Although Jeffords’ office did not immediately return calls seeking comment this morning, The Associated Press is confirming the report.

Rep. Bernie Sanders (I) has made clear that he is ready to jump immediately into any open Senate race in the Green Mountain State.

Democrats likely would give Sanders, who often votes with them, a pass while Republicans are expected to turn to either Vermont Gov. Jim Douglas or Lt. Gov. Brian Dubie for the Senate race.

Jeffords temporarily put the Senate under Democratic control when he bolted the GOP in 2001, earning the ire of Republicans across the country who would have liked nothing more than to defeat him next year.