Democratic and Republican sources say that Sen. Joe Lieberman, the independent Democrat from Connecticut and fierce supporter of the war in Iraq, will formally endorse Sen. John McCain tomorrow in New Hampshire.

A McCain spokesperson declined to comment.

A source familiar with the endorsement said that the two will appear of NBC's Today Show tomorrow morning and at a town hall meeting in New Hampshire.

The endorsement could help McCain with independents in the state. Combine that with news that Rudy Giuliani is scaling back his advertising buy there, that the Boston Globe endorsed McCain, and that McCain's rivals are spending most of their time in Iowa.

The endorsement is further evidence of Lieberman's slow drift to the right in American politics and is bound to generate intense anger among Democrats who support him. But Lieberman and McCain have often walked in lockstep together on the prosecution of the war, have traveled to Iraq together, and have worked together on domestic issues like climate change.

The move will heighten speculation that McCain might ask Lieberman to join his ticket.