CLEVELAND — Donald Trump and Mike Pence, having bungled the formal unveiling of their partnership as the 2016 Republican presidential ticket, tried Sunday to disprove the adage that you never get a second chance to make a first impression.

In their first joint interview, the celebrity billionaire and the Indiana governor portrayed themselves as tough and resolute enough to handle the cascade of crises that have gripped the nation and the world in recent weeks – and as a sharp contrast to the leadership style of President Obama and former Secretary of State Hillary Clinton, who will be nominated next week as the Democrats’ pick to become the 45th president.

“We’re both ready. I have no doubt,” Trump told correspondent Leslie Stahl of CBS’s “60 Minutes” in an appearance that aired on the eve of Monday’s opening of the Republican convention here.

Their coordinated message was a sharp contrast from an event Saturday in New York, billed as the formal announcement of Pence’s selection.

Saturday’s event went off the rails as Trump stood alone at a badly lit lectern that bore only his name and gave only glancing attention to his new running mate. Instead, Trump reprised his primary victory, rehashed his grievances and launched broadsides against Clinton.

On Sunday, the two sat side by side and reinforced each other’s arguments.

Noting the rise of the Islamic State, also known as ISIS, Trump contended that “Hillary Clinton invented ISIS with her stupid policies. She is responsible for ISIS. She led Barack Obama because I don’t think he knew anything; I think he relied on her.”

Pence added that “the larger issue here is declining American power in the world.”

“I truly do believe that history teaches that weakness arouses evil,” the Indiana governor said. “And whether it be the horrific attack in France, the inspired attacks here in the United States, the instability in Turkey that led to a coup – I think that is all a result of a foreign policy of Hillary Clinton and Barack Obama that has led from behind and that has sent an inexact, unclear message about American resolve.”

The interview was taped before the latest wrenching tragedy, Sunday’s killing of three police officers in Baton Rouge. It was unclear whether they were targeted as a reprisal for the fatal shooting by police of an African-American man this month.

With the convention due to begin, Republican Party elders and Trump campaign officials fanned out across the Sunday programs in an effort to set the stage with a show of unity and to tamp down the internal discord that remains a subcurrent of the four-day convention. It stems largely from the unconventional nature of Trump’s candidacy, and the fact that he ran as a repudiation of the party establishment.