MSNBC
During his appearance on Maddow's show on Tuesday, Johnston argued it was "entirely possible" that Trump himself sent the documents, saying that Trump has "leaked all sorts of things" over the years.
In a series of tweets on Wednesday, the "Morning Joe" host pointed out that while the 2005 federal tax returns depicted the president in a more positive light than some expected - Trump paid a federal income tax rate of 25%, despite writing-off nearly $100 million in business losses - the fanfare surrounding their release helped overshadow questions about Trump's ties to Russia and the troubled rollout of the GOP's replacement for the Affordable Care Act.
The MSNBC anchor also dismissed CNN anchor Chris Cuomo, who questioned why Scarborough blamed Trump without solid evidence.
Scarborough's accusation also appeared to come at another low in the relationship between the MSNBC host and the president.
Throughout the 2016 presidential campaign and much of the transition, observers - including Cuomo - criticized "Morning Joe" hosts Scarborough and Mika Brzezinski for their close relationship with Trump, who at one point dubbed the hosts "supporters," and occasionally took informal political advice from Scarborough.
After a falling-out during the campaign in which Trump dubbed Brzezinski "crazy," the hosts and Trump appeared to mend fences in the transition period, helping them gain access and scoops on the incoming administration.
Trump's "Morning Joe" viewership is well documented - advertisers and guests have even appealed to Trump directly during the show to some success.
But the two hosts have ripped into many of the president's policy decisions and rhetoric since taking office, slamming his unfounded wiretap allegations, the rollout of his travel ban, and people in Trump's orbit like counselor Kellyanne Conway.
Last week, the president unfollowed both hosts on Twitter.
This one tax return is not bad for him because he cherry picked one return from over a decade ago and had it leaked to the press. https://t.co/P5cMuApGVe
- Joe Scarborough (@JoeNBC) March 15, 2017
The Trump camp released one positive tax return to distract from Russia hearings and the Trumpcare meltdown. That's painfully obvious. https://t.co/NLBVPJhwg6
- Joe Scarborough (@JoeNBC) March 15, 2017
To the first pro-Trump/Putin hack that says this one cherry picked tax return settles the tax issue for good:
Not even close. https://t.co/NLBVPJhwg6
- Joe Scarborough (@JoeNBC) March 15, 2017
1. Learn to write intelligibly.
2. Try to keep up. The reporter who was mailed the returns said Trump may have sent it.
3. This ain't hard. https://t.co/8LgyFt4Z0O
- Joe Scarborough (@JoeNBC) March 15, 2017