LAUSANNE, Switzerland — If American negotiators are ultimately able to conclude a “political understanding” with Iran on its nuclear program, as they said they were striving to do Thursday morning, the seeds might have been planted earlier in the week.

With only hours to go on Tuesday night before the end-of-the-month deadline that had been set by the White House, Secretary of State John Kerry and Energy Secretary Ernest J. Moniz stepped into a large tent erected in a luxury hotel here and dialed into a video conference with President Obama.

There was no way to meet the deadline, Mr. Kerry said from the tent, which was designed to defeat eavesdropping. The Iranians, he said, perhaps sensing that the deadline meant a lot in Washington and little in Tehran, were intransigent.