Filing as a write-in for the general could throw the election to the Democrat; but if the GOP nominee is a Paultard or a RINO (but I repeat myself), I might be willing to support such a strategy.
BTW, you posted earlier “No write-ins in primaries in TX and maybe anywhere.” Write-ins in primary elections certainly are allowed in some other states: just within the past 8 years, Charlie Wilson won the 2006 RAT primary in OH-06 as a write-in after failing to turn in 50 valid signatures (!) to make the ballot (Wilson then went on to win the general); Dave Loebsack of IA-02 also won his 2006 RAT primary as a write-in (after not turning in enough valid signatures) and then won the general; and Nancy Cassis ran as a write-in for the MI-11 nomination after Congressman Thadeus McCotter didn’t turn in enough valid signatures to make the ballot, leaving Paulistinian reindeer rancher Kerry Bentivolio as the only candidate on the ballot; unfortunately, Cassis lost to Bentivolio, and we’ll have to wait until the 2014 primary to replace him.
Thanks, I don’t think any southern state has write-ins for primaries; if they do, it rarely matters. Thurmond and Skeen won as write-ins in SC and NM in general elections.