[MikefromOhio]

He might see that there is more that CAN be done in Congress instead of making an attempt at the Presidency and possibly losing.

He has a fairly secure grasp on his seat in Congress. He can do more there than in the Presidency IMHO.

[Once-Ler]

He might see that there is more that CAN be done in Congress instead of making an attempt at the Presidency and possibly losing.

Then we could conclude that his stand on immigration is only popular enough in his small congressional district to secure his future employment.