The Senate will on Monday ­challenge President George W. Bush’s proposed Iraq strategy with a debate on a non-binding resolution opposing the plan to send additional troops. However, several senators from both parties on Sunday warned it was unlikely to win the 60 votes needed for approval.

Republicans loyal to Mr Bush have attempted to undercut any political fallout from a resolution that would put on record the depth of cross-party dissent on the Iraq strategy. Their tactics include threats to filibuster a vote on the resolution and a “divide and conquer” strategy to allow votes on alternative resolutions.