Mitt Romney probably never imagined his current predicament, and certainly nobody else did: He was swept in the last three Republican primaries by the lightly regarded former Pennsylvania Senator Rick Santorum; trails Santorum by 10 points in the latest Gallup poll; and limps into his home state primary in Michigan next Tuesday - a contest he may well lose. The Republican establishment is becoming ever more noisily dissatisfied with his candidacy, and if he can’t prevail on Tuesday, several prominent members appear poised to demand that he step aside. Their concern isn’t hard to fathom.