Democrats clinch votes to open healthcare debate

WASHINGTON Nov 21 (Reuters) - U.S. Senate Democrats on Saturday clinched the 60 votes needed to open formal debate on a massive healthcare reform package after the last undecided Democrat, Senator Blanche Lincoln, said she would back the procedural move in a vote later on Saturday.

The Senate is due to vote at 8 p.m. EST (0100 GMT on Sunday) to open debate to reform the $2.5 trillion healthcare system -- President Barack Obama's top domestic priority.

Democrats need 60 votes to approve the motion in the 100-member Senate and have no margin for error -- they control exactly 60 votes and Republicans have been united in opposition.

(Reporting by Jeremy Pelofsky, Editing by Sandra Maler)