With the destruction of two potential candidates for the GOP Presidential nomination in 2012 (John Ensign and Mark Sanford) due to marital infidelity, the Republican field has narrowed considerably. However, the decline in fortune of some also leads to the growing role of others, as is seen by the appointment by Senate Republicans of John Thune of South Dakota as chairman of the Senate Republican Policy Committee, the fourth highest position within the party leadership.
This position gives Thune the opportunity to develop policy alternatives for the party in the Senate and put him more onto the national stage. This, plus his good looks, his oratorical ability, his youth, and the fact that there are no other Senators considered likely as presidential candidates at this moment, elevates him to the real possibility of a Presidential candidacy in 2012, if with his big war chest, he can win reelection in South Dakota in 2010, which at this point is seen as likely.
So even with some potential candidates falling off the list, at least one more can now be said to have been added.