Actually Trump denounced David Duke several times, but for some reason didn't when he was interviewed by Jake Tapper.
You have it backward, of course.
Trump refused to denounce David Duke on Jake Tapper, despite Tapper giving him chance after chance.
Then, when Trump realized this was a bad move and that it was hurting him politically, he then began to denounce Duke, "several times".
"...the successful annihilation of organized crime's subculture in America would rock the 'legitimate' world's foundation, which would ultimately force fundamental social changes and redistributions of wealth and power in this country. Meyer Lansky's dream was to bond the two worlds together so that one could not survive without the other." - Dan E. Moldea
