Speaking to USA Today in an exclusive telephone interview, Vance said he felt “extremely confident” that the US would not be talking about its involvement in Iran “even a year down the road.”

“I think that we’re going to be successful,” Vance told USA Today.

“If this diplomacy ultimately falls apart, then the president has further tools at his disposal. But so long as we keep this thing anchored to the core mission — prevent Iran from having a nuclear weapon — it’s not going to become a quagmire.”

The armed conflict — triggered by the joint US-Israeli strikes on Iran on February 28 — hit its 100-day mark this week. Since April, the war has been in a ceasefire that US officials, including Vance, have sought with limited results to advance to a comprehensive peace agreement.

Trump has repeatedly signalled that a deal is close, but negotiations have hit repeated deadlocks. Recent exchanges of fire between Iran and Israel had raised fears the ceasefire was fraying.

Vance, an Iraq war veteran and the administration’s most vocal skeptic of American military engagement abroad, did not rule out intensified US military action if diplomacy fails.

The vice president’s remarks came during a telephone interview tied to the release of his new book, Communion: Finding My Way Back to Faith, due for release June 16, a follow-up to his bestselling memoir Hillbilly Elegy