Washington (CNN) - Two steps forward, one step back.

A surge of optimism on Monday for a possible compromise to end the partial government shutdown and avoid a U.S. default as soon as this week got jolted by the sudden postponement of a White House meeting between President Barack Obama and congressional leaders.

In a brief statement, the White House said the meeting announced earlier in the day was put on hold "to allow leaders in the Senate time to continue making important progress" toward a solution.