1. This is a silly season. Nobody is actually casting a vote for Trump that counts and it will be months and months before real votes are cast. It will get better.
2. Trump might actually improve the discourse in the Republican primary. Since there is no point in trying to out-inflammatory Trump, it might create a primary to see who can consolidate the 75%-80% who even now won't back Trump. So the competition might be in the direction of being the anti-Trump rather than becoming Trump-lite. Good for Michelle Bachmann for renouncing the birther issue.
3. What are the odds that the whole Trump thing is a footnote by November of this year? I'd say at least 50/50.