Some analysts believe that Iran poses a greater threat to Americans than do Islamic State terrorists. They point out that while the IS murderers certainly are vicious, they lack the medium-range missiles in Tehran’s arsenal – and the nuclear weapons Iran seems on the threshold of developing if it chooses to do so.

Secretary of State John Kerry and other U.S. negotiators are working to complete by June an agreement with Iran that could postpone that country’s acquisition of nuclear weapons. A framework for that arrangement was announced Thursday.

Meanwhile, rebels in Yemen, backed by Iran, are being battled by a coalition led by Saudi Arabia.

In Iraq, Iranian generals are leading an Iraqi offensive against the Islamic State, with U.S. aid including airstrikes. The Iranians would not be there but for a power vacuum resulting from the early pullout of U.S. troops in Iraq.

Iran seeks to broaden its role across the Middle East.

So long as that country is led by a faction that has a strongly anti-American orientation an increase in Iranian influence is a problem.