Washington - The Republican Party chair says Donald Trump is "getting into a groove" in his presidential campaign against Hillary Clinton.
Reince Priebusis predicting Trump would pull even with Clinton in polls by around Labour Day.
He told ABC's This Week that "Trump's been disciplined and mature, and I think he's going to get this thing back on track".
Trump shook up his campaign this past week, installing a new chief executive, Stephen Bannon - former head of conservative news site Breitbart News.
Priebus was shown a clip of Bannon talking approvingly of plans "to destroy" the congressional leadership. The GOP chair said he was "never happy" with criticisms of "great leaders" like House Speaker Paul Ryan.
But, he added: "People can pivot into different roles and ultimately the person in charge of Donald Trump's campaign is Donald Trump."