While intense attention is focusing on whether or not President Trump will opt to decertify the Iran Nuclear Agreement Renewal Act of 2015 by this weekend — more on that below — Jerusalem is more worried, for the moment, about the prospect of Iran establishing a permanent military presence in Syria. That would represent a danger Israel could not allow.

Alex Fishman, a leading Israeli military analyst, reported in Yediot Achronot last week that Iran is planning to build a military air base near Damascus, and discussing establishing a naval presence in the port of Tartus. Teheran might also send a division of soldiers to Syria.

In an effort to deal with this pending crisis, a series of diplomatic meetings will bring Russia’s defense minister to Israel next week, followed by Israeli Defense Minister Avigdor Lieberman flying to Washington for talks with Secretary of Defense James Mattis. So far, Israeli Prime Minister Benjamin Netanyahu has been unsuccessful in his four meetings in Moscow in the last year urging Russian President Vladimir Putin to convince Iran’s leaders not to expand their military presence in Syria. So far, Israel has acted when it felt necessary, bombing sites in Syria when Iran sought to bring in sophisticated arms.

In his Washington meetings, Lieberman is expected to emphasize Israel’s chief objections to the Iran nuclear deal: the fact that it has a “sunset” provision, a limited shelf life after which Iran can resume its nuclear weapon plans; that it does not include a ban on ballistic missiles or inspections of military sites; and it doesn’t address Iran’s support of terror groups like Hamas and Hezbollah.

President Trump has made it clear, often and forcefully, that he believes the Iran nuclear deal was a terrible one. But so far he has been persuaded by his top military and security advisers that to tear it up, as the president promised he would, could lead to Iran resuming its nuclear efforts without delay. That would leave the U.S. with another North Korea situation: a potential military showdown, with enormous and deadly consequences, as a result of failed negotiations.

Reasonable arguments have been made of late, pro and con, on Trump’s option to decertify. Such a move would not affect the nuclear agreement itself, but rather shift responsibility from the White House to Congress, which could re-impose economic sanctions on Iran. Michael Oren, Israel’s deputy minister of diplomacy, has echoed Prime Minister Netanyahu’s “fix it or nix it” call to renegotiate a tougher deal with Iran or cancel it and levy “crippling sanctions.”

Defenders of the deal point out the imminent danger of Iran walking away from it if Washington pushes too hard, and the importance of the U.S. working in sync with allies like Britain and France, which have called on Washington not to pull out of the nuclear deal.

Taking the middle road, Mideast expert Dennis Ross stresses the importance of the European allies but sees an option in the U.S. decertifying — with the caveat that it is not canceling the deal or calling for sanctions yet. Rather, Ross suggests, the U.S. could explain that it is putting the agreement on hold for six to 12 months to see if Iran will address its sunset provisions and its testing of ballistic missiles and “regional misbehavior” in Syria, Iraq and Yemen. If that pressure doesn’t pay off, the U.S. could walk away from the deal.

In the meantime, the increasing military presence of Iran in Syria could lead to a more immediate showdown.