Why are Iranian officials preaching to their amen corner at the United Nations at the same time that their henchmen seek to assassinate a man vying to become America’s next president? As President Pezeshkian of Iran spoke at the United Nations yesterday, President Trump’s campaign disclosed details of a briefing he received from our top intelligence aide. It detailed Iran’s “continued and coordinated attacks” on his and other former officials’ lives.

“We’re looking at it very carefully,” Secretary Blinken told NBC this morning. How about acting on it instead? America, as the host nation, is obliged by treaty to accommodate all who wish to participate in UN activities. Yet, Congress has carved out an exception, allowing for denial of entry to anyone posing a threat here. That could well define the large delegation from a country that threatens American citizens, including President Trump. 

Regardless of President Biden’s affinity for the world body, loudly heard in his self-congratulatory swan song at the General Assembly yesterday, shouldn’t he and his would-be successor, Vice President Harris, look out for America first? Denying Mr. Pezeshkian a visa might be out of character for an administration that shies away from confronting enemies. Even within these confines, though, a significant, even symbolic measure could go a long way. 

Foreign Minister Abbas Araghchi is an architect of Iran’s “resistance diplomacy,” which, as United Against Nuclear Iran describes it, “balances dialogue with the West and unwavering support for Iran’s terrorist proxies.” Mr. Araghchi is also closely affiliated with the Islamic Revolutionary Guards Corps, the body that oversees assassination attempts abroad. Why should he be admitted to New York’s East Side?

Another man in Mr. Pezeshkian’s entourage, Javad Zarif, Iran’s vice president for strategic affairs, has for years cultivated an American fan club. This morning, in an “exclusive” interview, he told MSNBC’s Andrea Mitchell that Iran has “no interest” in changing America’s election results. The former foreign minister’s charm offensive aside, why is he here? He has not even been photographed in any of the president’s meetings with world leaders.

Closely associated with the 2015 Iran deal, Mr. Zarif’s sole purpose in accompanying Mr. Pezeshkian, then, is to spread Tehran’s propaganda. Denying him entry could have been a powerful message that Washington no longer tolerates smiling assassins. That is, of course, unless this administration, like some in its press accolades, is buying the smile, while overlooking the dagger it conceals.

America’s eagerness to accommodate potentially dangerous guests doesn’t end with Iran. This week the Department of State announced that Qatar would become the first Gulf country to participate in its visa waiver program. By December Qataris can visit America for 90 days simply by showing up at JFK. Doha is home to top Hamas leaders. It is also Mr. Biden’s go-to liaison in negotiations with Hamas murderers, rapists, and hostage takers. 

Mr. Biden’s officials have praised Qatar’s diplomatic efforts, while briefing reporters that Israel is blocking a Gaza deal. Mr. Pezeshkian’s UN speech, in which he expresses readiness to return to the 2015 nuclear deal, might whet appetites in some Washington circles. Regardless of its diplomatic failures, the Biden-Harris administration appears willing to entertain any attempt at diplomacy — including with those who wish America ill.