Senate Republicans were unable to muster enough votes Thursday for a bill opposing another $1.2 trillion increase in the debt ceiling.

The measure was defeated on a 52-44 vote. Lawmakers would have needed 60 votes in order to push the bill through, and more than that to override a presidential veto. The House had approved the measure last week, but it was expected to fail in the Senate.

The vote caps an unusual process set up at the end of the debt-ceiling debate last summer. The process allows lawmakers, mostly Republicans, to vote against debt increases but not actually block them. Blocking them would provoke a first-ever, market-rattling default on U.S. obligations.

The vote split mostly along party lines. One Republican, Massachusetts Sen. Scott Brown, opposed the measure. Two Democrats -- West Virginia Sen. Joe Manchin and Nebraska Sen. Ben Nelson -- supported it.

"Look, we should be working together to lower the debt, not having votes to increase it," Senate Republican Leader Mitch McConnell said Thursday. "No more blank checks."

Republican Pennsylvania Sen. Pat Toomey said the government must "live within their means"...