Obama just secured victory on his signature foreign policy achievement

President Barack Obama has received enough pledges of support in Congress to ensure that one of his signature foreign-policy goals will remain intact.

Sen. Barbara Mikulski (D-Maryland) on Wednesday announced support for the Iranian nuclear deal. It brings the number of senators supporting the deal to 34, the key threshold to ensure that it can survive Congressional opposition. Obama needed pledges of at least 34 senators to stave off a potential veto override led by Republican members of the Seante.

The deal's opponents are set on passing a vote of disapproval of the deal. But Obama has pledged to veto any such disapproval, which means opponents would need two-thirds majorities in both the House of Representatives and the Senate to override that potential veto.

Now, the Obama administration and proponents of the deal are hoping they can gather enough support so that Obama will not have to veto a bill at all.

So far, only Sen. Chuck Schumer (D-New York) and Sen. Bob Menendez (D-New Jersey) have said that they will vote against the agreement. If proponents can ensure that at least 41 members of the Democratic caucus support the agreement, they will be able to block the bill's passage.

Mikulski is not seeking re-election and is set to retire from the Senate in 2017.