If it comes down to Gingrich/Romney/Paul as some of these polls seem to imply it may, then eventually Mitt will wear down the two old men with no money and little campaign infrastructure.
The biggest fear Romney should have regarding Iowa is that the Iowa result somehow invigorates Perry or gives hope to Santorum. (I think GOP men recognize Bachmann for the kook she is, so they will never allow her to win).
If the Oven Mitt has to go to the South facing someone like Perry or Santorum, suddenly backed by power brokers and now receiving new cash, he is done. Recall that in 2008 Romney finished THIRD in most primaries in the South. McCain, Huckabee, then Romney.
Romney would be happy with a 3rd place in Iowa if it went Paul 30; Gingrich 27; Romney 23; Perry 8; Bachmann 7; Santorum 5.
If, instead, Romney wins and it goes Romney 26; Paul 25; Perry 21; Santorum 14; Gingrich 12; Bachmann 2 then Willard has some real problems ahead.