Vice President JD Vance, who was actually in India at the time of the assault, played an instrumental role in negotiating the ceasefire. It was decided he would get the job of calling Indian Prime Minister Narendra Modi:

In his noon phone call with Modi, Vance made it clear that the U.S. believed that there was a high probability of dramatic escalation as the conflict went into the weekend.

The vice president encouraged Modi to consider de-escalation options, including a potential off-ramp that U.S. officials knew the Pakistanis would be amenable to.

Officials from all sides stayed up into the wee hours working for a breakthrough:

Modi listened to the vice president’s message, although he didn’t explicitly indicate openness to any of the options put forth.

Vance's call to Modi came less than a month after he met with the Indian leader in New Delhi to discuss trade talks.

From that point, key U.S. officials continued to work the phones with their counterparts in India and Pakistan into the night to help re-establish communications between the two sides, allowing them to work out terms for a ceasefire in the next 12 to 18 hours.