Reuters is reporting:

President George W., Bush plans on Tuesday to veto a war spending bill that imposes timelines for a U.S. troop withdrawal from Iraq, and will then explain his action in a statement at the White House, an administration official said.

Bush will carry out his long-standing threat to veto the legislation after returning from a visit to U.S. Central Command in Tampa, White House National Security Council spokesman Gordon Johndroe said.

The president’s statement was scheduled for 6:10 p.m. EDT (2210 GMT), he said.

And TPM has the video of a new ad that will be running nationally after that:

 And so the showdown begins.