Obama, with both hands tied behind his back, head butts the GOP out of the ring.
UN Security Council has endorsed the Iran deal which now renders the decision of USA congress as irrelevant because trade with Iran is now permissible.
This will be a big boost for world trade, although USA is not likely to gain from the trade boost because of residual hostility of Iran to USA.
The big gain Obama received form this was to have the GOP-led Congress rendered impotent consequent to UNSC declaration.
Obama smashes GOP out of the ring again.
I do not know if this Iran thing is good or bad. But you are right about congress becoming irrelevant. It use not to be that way. But when what ever party holds the white house, members of that party in congress become members of the administration instead of congress. There was a time when congressmen respected their institution and would not let any administration take power from the congressional branch. Those days are long gone. Party loyalty has replaced institutional loyalty and respect.