When a chief executive can violate multiple articles of the oldest functioning constitution in the world and disobey statutes he solemnly swore to defend and execute faithfully, then blame judges who never even asked him to intervene, he mocks the principle of limited government and the separation of powers. He robs Americans of their unalienable right to self-government, for which so many soldiers, sailors and airmen have died.
These are just two issues (there are more) that absolutely disqualify Mitt Romney as a viable Vice Presidential option. He would fatally harm your appeal to voters with deep constitutionalist and social conservative commitments.
If Governor Romney is on your ticket, many social conservative voters will consider their values repudiated by the Republican Party and either stay away from the polls this November or only vote down the ticket. For the sake of your election, the health of your party, and the future of America you must not allow the obvious electoral consequences of that to occur.
And now on Newt:
Temperamentally, there is nothing that suggests that he wouldn't make a decent President. Contrary to all of the fol de rol of the sparks and fury that he creates, he is very pragmatic underneath and he does not do things that are terribly foolish. Most of what he does, he knows precisely what he's doing.
The whole piece is pretty extensive and definitely well worth the read.