Two former Obama administration officials suggested in a New York Times op-ed published Thursday that European countries allied with the United States could expel American ambassadors in retaliation for President Donald Trump withdrawing from the Iran nuclear deal.

"Europe Doesn't Have to Be Trump's Doormat," wrote Steven Simon and Jonathan Stevenson. Simon served as the National Security Council's senior director for the Middle East and North Africa, while Stevenson served as the regional director for political-military affairs.

"After months of swaggering hesitation, President Trump finally announced the United States' withdrawal from the nuclear deal with Iran, to which Britain, France, Russia, China, Germany, and the European Union are also parties," they wrote. "This action tramples on European leaders, who urged Mr. Trump to exercise restraint in the interest of international security and multilateralism."

The two men urged European countries to go beyond "mere words" and counter Trump's withdrawal from the Iran nuclear deal with real, concrete actions.

"The European Union could, for instance, announce the withdrawal of member-states' ambassadors from the United States," they suggested. "Isn't this what states do when diplomatic partners breach solemn agreements, expose them to security risks and threaten to wreak havoc on their economies?"

Simon and Stevenson went on to suggest that, depending on how the United States reacted, "European capitals might even follow up with expulsion of American ambassadors."

As the U.S. and other world powers negotiated the Iran deal in 2015, the Obama administration was critical of what its officials described as Republican efforts to undermine negotiations. Vice President Joe Biden complained that Republicans "undercut a sitting president in the midst of sensitive international negotiations," while Obama himself accused them of making "common cause with the hardliners in Iran."