First of all, McCain dove into a presidential campaign knowing that he still had a job to do as Senator. If he doesn't feel he can do that job while running for President, perhaps he should resign his Senate seat. Or, you know, give back his nomination. I've never been one of the folks who thought McCain was too old to be President, until now. Announcing you can't handle both politics and the business of the country at the same time makes you seem the doddering old man some opponents have painted you as, Senator.
Senator Obama has a choice to make, here. He can follow in McCain's pandering footsteps, and act as though the financial crisis was a complete shock that suddenly needs all his attention. Or he can act presidential, and focus on doing his job as Illinois Senator while continuing to try convincing the American people they should vote for him.