Iran will get a nuclear bomb. Its just a matter of time. Some say in as little as 3 years, and others believing up to 10. At that time, President Obama and the Democrats will be forced to own that fact.
Last week, Harry Reid gained just enough votes to procedurally avoid the embarrassment of the President having to veto a Senate "no vote" on the Iran deal. Following that, all the House Republicans and only 25 Democrats won a symbolic vote that disapproved of the Obama led deal. Whether or not he ever saw a dissenting vote from both Houses of Congress, the President will still be politically responsible for Iran getting the bomb.
This will definitely be a problem for the Democrats in 2016. A recent CNN/ORC poll showed that 59% of those polled disapprove of the President's negotiations with Iran. Thus, by proxy, those Democrats who voted to "not" go against the President share in the nation's dissatisfaction with the so-called "deal".
Once again, politics trumps what is good for the nation and what is good for our only real ally in the Middle East: Israel.
Senate Democrats protect Obama on Iran vote: http://www.cnn.com/2015/09/10/politics/iran-nuclear-deal-vote-congress/
House goes on record against Iran nuclear deal, in symbolic vote: http://www.foxnews.com/politics/2015/09/11/house-defeats-measure-approving-iran-deal-in-symbolic-vote/
Poll: Americans skeptical Iran will stick to nuclear deal: http://www.cnn.com/2015/09/13/politics/iran-nuclear-deal-poll/