Donald Trump is becoming more formidable as his campaign becomes increasingly professional, Democratic former Rep. Harold Ford Jr. said Wednesday. Ford, now a Morgan Stanley managing director, offered his assessment one day after the Republican presidential front-runner won the GOP primary in New York. In addition to bringing on new campaign staff, Trump showed discipline during his victory speech by referring to his opponent as Sen. Ted Cruz, rather than "Lying Ted," as he has in the past, Ford said.

"If this is the transition and pivot he's going to make, I've said to my party and my candidate, I think we win, but Donald Trump will be a tough opponent between now and November," he told CNBC's "Squawk Box." Hillary Clinton, who won the Democratic contest in New York, cannot necessarily rely on poor favorability ratings for Trump because she is also unpopular with many Americans, he said. A recent NBC News/Wall Street Journal poll found that 65 percent of Americans have a negative view of Trump, while 56 percent were sour on Clinton. "I don't think we'll see a race in the near term — because we focus on this for such a long period of time — where the nominees come out of the party with higher favorables than unfavorables," Ford said.