WASHINGTON -- In the matter of Mitt Romney's selection of Rep. Paul Ryan, R-Wis., to be his running mate, I keep flashing on images of Wallace Shawn in "The Princess Bride": Inconceivable!

Here's a rule of thumb: If you are the Republican nominee and The Wall Street Journal editorial page, The Weekly Standard and National Review are all urging you to do the same thing, run the other way. Romney doesn't need the base; if they are not enthusiastically for him, they are enthusiastically against Obama, which ought to be enough.

Romney needs independents in Virginia, suburban women in Colorado, seniors in Florida. It's not a question of whether Ryan will help him woo these voters; it's a matter of whether Ryan -- especially once the Obama campaign and associated super PACs get through with him -- will make that even harder.