The agreement to halt some aspects of Iran’s nuclear program in exchange for temporary relief from international sanctions is being hailed as a breakthrough in U.S.-Iranian relations, a detente after decades of animosity.

Proponents of the U.S. efforts to seek a diplomatic solution to the nuclear quandary claimed that the regime came to the table because recent world sanctions crippled the Iranian economy. There have also been suggestions that Iran’s new “moderate” regime is pursuing real changes as a way to join the global economy.

Geopolitical reality, however, offers a different perspective on Iranian motivations. Iran is locked in a brutal and expensive proxy war in Syria supporting the regime of Bashar al-Assad. Its primary adversaries, Saudi Arabia and the other Gulf states, have funded and armed the largely Sunni resistance movement. The conflict is at a stalemate. Government forces have difficulty exercising any measure of control outside of Damascus. As a result, external support may be decisive. Iran is at a disadvantage because global sanctions have cut the oil profits used to finance Assad’s forces.

The U.S. sanctions imposed over the last several years ingeniously strengthened existing multilateral action by adding further restrictions and making the U.S. a unilateral enforcer.

Iran has had plenty of opportunities to take steps in reducing the tension over its efforts to build a nuclear bomb, but, before the latest round of negotiations, it has always opted to pursue the weapons at the expense of economic gains. The recent deal seems to be a departure. President Hassan Rouhani’s government is seen as more moderate than its predecessor. It has also proved adept at navigating geopolitics and advancing its interests. The U.S. decision not to order airstrikes on Syria this summer might have relieved some of Iran’s fears, creating an opening to make the regional conflict its top priority and invest in protecting Assad.

Even assuming Iran is acting in good faith with this week’s nuclear deal, we should prepare appropriate steps should the agreement sour over the next year. Some part of the $7 billion Iran will secure after oil sanctions are suspended will probably make its way to Syria and also fund Hezbollah fighters in the country. Should that financing be sufficient to prolong the proxy war for an additional six months, it will be interesting to see whether Iran is willing to leverage its nuclear ambitions a second time before the U.S. demands a long-term deal next year.

(Scott Helfstein is the director of strategic initiatives for the Combating Terrorism Center and an assistant professor at the United States Military Academy.)

To contact the writer of this article: Scott Helfstein at scott.helfstein@usma.edu.

To contact the editor responsible for this article: Alex Bruns at abruns@bloomberg.net.