Donald Trump has already demonstrated his willingness to back out of scheduled debates and appearances. On Tuesday he indicated he may do so again. 

The Republican presidential front-runner tweeted Tuesday a threat to pull out of a televised town hall in Wisconsin that is set to air Tuesday night on CNN. The apparent motivation is Trump's frustration with what he considers unfair coverage of his campaign in comparison with his GOP rivals.

The three remaining GOP presidential candidates — Trump, Texas Sen. Ted Cruz and Ohio Gov. John Kasich — are scheduled to participate in the town hall event in Milwaukee, which kicks off at 8 p.m. EDT and runs until 11 p.m. CNN anchor Anderson Cooper is set to moderate at Milwaukee’s Riverside Theater. The Wisconsin primary is April 5.

In his tweet, Trump claims CNN has been giving his opponents excessive air time in comparison with his own campaign. But he may have other reasons to think the town hall might leave him unnecessarily vulnerable. 

Trump took part in a contentious radio interview Monday with Milwaukee radio host Charlie Sykes, who asked if Trump was willing to apologize about recent controversial remarks the front-runner made about Cruz's wife, Heidi, and Wisconsin Gov. Scott Walker. The exchange turned combative. 

“Obviously, I failed in my effort to introduce you to Wisconsin and our tradition of civility and decency by getting an apology from you for Heidi Cruz or for what you’ve said about Scott Walker,” Sykes said, Politico reported. Walker endorsed Cruz Tuesday.

Then on Tuesday, police charged Trump's campaign manager Corey Lewandowski with misdemeanor battery following an incident with then-Breitbart reporter Michelle Fields at a March 8 rally.

The town hall, where Trump would face questions from Wisconsin voters directly, might seem like too much of a wild card to the candidate after the recent controversies. However, with 42 delegates at stake in the state's April 5 primary, skipping the event would be a risky strategy.