Donald Trump hired another top aide of a one-time rival, inking Chris Christie’s former campaign manager Ken McKay.

McKay will join a team that now includes at least two other political operatives who once ran campaigns of 2016 GOP presidential candidates — Rick Wiley (Scott Walker) and Ed Brookover (Ben Carson), Trump aides told Bloomberg News.

“This (McKay) is a serious strategist and tactician,” said Curt Anderson, chief strategist for former White House hopeful Bobby Jindal. “This is not a guy who wastes his time going on cable TV and running his mouth. Trump hiring Ken McKay is a bad thing for the Ted Cruz campaign, I can assure you of that.”

Trump is leading the GOP presidential race, but struggling to clinch the nomination before the Republican National Convention this summer in Cleveland.

His two remaining rivals, Cruz and John Kasich, agreed Sunday night to an extraordinary non-aggression pact in a bid to stop Trump.

Kasich has agreed to not campaign in Indiana, while Cruz has pledged to steer clear of Oregon and New Mexico.

Trump was in full mock mode on Monday, calling the unorthodox campaign tactic a desperate move.

“Collusion is often illegal in many other industries and yet these two Washington insiders have had to revert to collusion in order to stay alive,” Trump said in a statement.

“They are mathematically dead and this act only shows, as puppets of donors and special interests, how truly weak they and their campaigns are. It is sad that two grown politicians have to collude against one person who has only been a politician for ten months in order to try and stop that person from getting the Republican nomination.”