It’s an escape hatch for Senate Democrats who have trapped themselves
in a highly unpopular effort. Even the New York Times thinks this is a
bad idea.

http://www.nytimes.com/2009/12/11/he...sure.html?_r=1

“Extending this successful program to those between 55 and 64 would be
the largest expansion of Medicare in 44 years and would perhaps get us
on the path to a single-payer model,” said Representative Anthony
Weiner, Democrat of New York."

Yep - that's about it. Well, single payer for everybody except for
Federal, State and Union employees - they get to keep their private
insurances.