I don't recall a more weak campaign move than what John McCain is doing right now. After being in DC for a few decades, he decides he wants to finally do something in the midst of his own presidential campaign. How can this even be defended? Imagine if Reagan would've pleaded not to debate Carter in 1980 because of the Iran hostages or if Bob Dole would have stayed in the Senate and said, "Bob Dole's busy, you go on without me Bill."
If you want to be a Senator, be a Senator. If you want to be President, you run for it even when you're losing. If you want to do something about the economy, you should've done it when you had decades to work on it.