A liberal pro Israel lobby group is spending $630,000 on television ads in Pennsylvania to pitch the nuclear agreement with Iran as crucial to the security of the Jewish state, part of a five-state campaign aimed at crucial members of Congress.

In the 30-second spot, set to begin airing Wednesday, J Street quotes figures in Israel's national-security establishment who support the deal. The idea, the group's leaders say, is to counter the intense opposition of Prime Minister Benjamin Netanyahu – and many U.S. supporters of Israel on the right - to the agreement.

The 15-year deal, negotiated by the U.S. and other world powers, would lift economic sanctions against Iran and allow it to have nuclear power, but bar the country from developing nuclear weapons, with a regime of inspections and restrictions to enforce the ban.

Opponents say there are loopholes in the agreement that would allow Iran to get the bomb.

Congress is on summer recess, but when it returns to Washington in September, the House and Senate could schedule votes to reject the deal. President Obama has vowed to veto any such attempt.

In addition to Pennsylvania, J Street is airing the ad in Maryland, Michigan, Colorado and Oregon for up to three weeks. The group announced it will spend a total of $2 million on the campaign.

"The bottom line is that many leading Israeli security experts believe, like the majority of American Jews, that this deal is the best option for the U.S. and for Israel, and that it makes both countries safer," said J Street President Jeremy Ben-Ami.  "It's critical that our elected leaders know the facts as they head home for recess and headlong into the debate swirling around this deal in their home communities."