The role played by John McCain appears to have been a constructive one. He supported and worked with the House Republicans. The Democrats no doubt wanted his support for the final product, and that must have enhanced the Republicans' position at the table. The Democrats would not have wanted an unpopular bailout plan to be supported by Barack Obama and opposed by McCain.
If voters understood the events of the last week, they would probably return control of the House, and perhaps the Senate, to the Republicans. The mainstream media will make sure that doesn't happen.
Political implications aside, we better hope and pray that this package does settle things down and restore confidence in the financial system, given the dire consequences of failure seen by some of those knowledgeable in the financial field.