In Milwaukee, a G.O.P. Transformation From Dysfunctional to Unified

For eight chaotic years, Republicans battled in public and private, fighting over Donald J. Trump’s polarizing personality, his divisive policies and his history of electoral defeats through lawsuits and leadership battles, felony convictions and suburban defections.

Yet even before a single balloon has dropped at their national convention this week, Republicans have united — seemingly without reservation — behind the man and his message. Across downtown Milwaukee, delegates, officials and lawmakers appeared to be taking a victory lap in the middle of a race that many believe is breaking their way, galvanized by a would-be assassin’s bullet and the chaos gripping the rival party.

Even Mr. Trump’s most potent Republican primary foe, Nikki Haley, was greeted on Tuesday with a standing ovation as she testified to his fitness to return to the White House — an issue she had often questioned on the campaign trail.

“President Trump asked me to speak to this convention in the name of unity,” Ms. Haley said, adding: “I’m here tonight because we have a country to save. And a unified Republican Party is essential for saving her.”

It is a party-wide evolution that would have been difficult to envision eight years ago, when Mr. Trump first burst onto the Republican stage, or as recently as this spring, when the party was recovering from a bruising primary contest and the serial humiliations of a dysfunctional House majority that struggled to select its own leadership. Then, Mr. Trump was a liability and not the party’s great unifier.

Now, the shift in mood was striking: It has been decades since those at any Republican convention felt quite so confident — even optimistic — that they had the right candidate, the right causes and the right