In "The Mythical Man-Month," software manager Frederick P. Brooks Jr. explained that adding workers to a software project that was behind schedule would only slow the project down, and not speed it up. This happens because adding new workers forces the existing workers to stop what they are doing to explain to the new workers what has been done, what needs to be done, and what is being done, as well as the increase in time needed for communications among a greater number of workers.
For similar reasons, John McCain's decision to suspend his campaign in order to travel to Washington to intervene in the Congressional efforts to fix the current mess in the nation's credit markets can only slow things down, and not speed things up.
McCain admits he knows nothing about economics, and has also admitted that, as of two days ago, he had not yet read Treasury Secretary Henry Paulson's three-page bailout proposal. It will therefore take a great deal of time to bring McCain current on the economic and political issues at stake, as well as the history and current state of the negotiations within Congress and between Congress and the executive branch.
Unfortunately, McCain can't tell the difference between leadership and showboating, which is why he will almost certainly make things worse instead of better.