The $100 gas rebate in border protection
Remember that $100 dollar rebate that Bill Frist proposed to combat high gas prices. It was seen as a temporary fix to a long term problem while being too little to late, and was pulled days later.
Posting national guard troops on the border is the same policy on a different issue. It's a short term fix and if the President really felt this strongly about immigration, he would have proposed this long ago.
It's little more than a fig leaf to conservatives who are dissatisfied with the President, and I'm not sure how much good it's going to do.