That isn't a big mystery. They don't want to risk a government shutdown which they assume would play out badly for us.
I don’t believe the fear of being blamed for a shutdown. Any competent PR and marketing firm can help craft a winning communications strategy explaining to the people it is the president’s veto of the spending bill shutting down the government, not the failure of Congress to pass a bill.
The real reason Congress gives Obama what he wants is extortion. His files include details about mistresses, drug abuse, payoffs, tax evasion, and other care ending information. Even if the Congressman is clean, Obama has the dirt on family members. What GOP Congressman wants his wife’s abortion or son’s battle with drug addiction to become public knowledge.
I strongly suspect the prosecution of Dennis Hastert for breaking a law pertaining to bank withdrawals was the cover to out him for homosexuality and pedophelia. This outing occurred only a few months before the Republicans completely caved on the budget. The Hastert outing was a message. Those receiving the message performed as expected.