Everyone else in a position to know, in not only the previous but the CURRENT administration, has categorically denied it, noting (among other things) that NO FISA warrant for such an action exists nor was ever even sought. Pressed to prove up or shut up, Trump offers only this:

Of course, the only "reports" about his allegations are Trump MAKING them; citing oneself as a "source" just will not fly. Yet the latest tweet still contains some inadvertent truth: He wants the Congressional investigations into his 1) campaign manager, 2) NSA Director, 3) Atty. Gen. and 4) son-in-law meeting with Russian officials during and after the election Russia was hacking to INSTEAD focus on his "fake news" about Obama. Maybe they can find his birth certificate (again) while they are at it.

He is really just recycling a "story" from one of the House Republicans a few weeks ago, dismissing the treason to insist the "real" issue is "why was the US government tapping one of its private citizens phones?!eleven" The answer, of course, is "it was not: It merely tapped the RUSSIANS phones and Mike Flynn just happened to call. Five times in a single day."

My favorite part is explaining away all the meetings with the Russian ambassador as routine because all the Trump campaign staffers were at the Republican National Convention, and the Russian ambassador was also there because he was invited.

See? The Republican Party just invited the Russian ambassador to the convention that nominated their presidential ticket; no big deal.

That will make it a lot harder to just blame the whole thing on Trump, impeach him, excuse the rest of the GOP, and smoothly swear in Pence.