Because 17 senators thought Alito did not belong on the US Supreme Court, and signified such by voting "no" on his nomination, but were unwilling to stand up one day earlier and vote "no" on closing debate so he could be confirmed. 17 statewide-elected politicians who thought the man did not deserve a lifetime appointment to the nation's highest court, yet refused to vote "no" when it counted.

Taegan Goddard has it right:

Quick analysis: Had everyone who opposed Alito backed a filibuster, he wouldn't be a Supreme Court Justice today.

We need to replace the Democrats that always punt on third down.