Here is my view on the topic.
- Is Obama over stepping his authority? - probably
- What can congress do? - well the constitution sets down some clear areas where the congress could act:
a. The congress probably has grounds to impeach the president (they won’t and don’t have the votes to convict)
b. The congress could stop funding the Executive Branch (that would cause a government shut down and the GOP has said they will not do that)
c. They could pass a law revoking what the president did (that is unlikely to be signed by the president and it is unlikely they will have the votes to over ride a veto.)
So congress really doesn’t have anything they can do except partner with the Executive Branch on a revised immigration law that both sides will endorse (or just let what the president did stand.)
I don’t think individual congressmen have standing to file a suit since they can’t show they were personally harmed.
A State may sue if they can show they have to expend money or otherwise harmed by this action; as the article points out two states have started actions to do that. It may or may not get to the SCOTUS for decision in 2016. The cases may be interesting to watch.
my 2-cents.