Joshua Black, a Republican candidate for Florida’s state House of Representatives, tweeted Monday that President Obama should be hanged for treason.

Black, a taxi driver and former street evangelist, is challenging state Rep. Dwight Dudley (D) this November in the St. Petersburg-based 68th district. On his campaign website, he complains that “Republicans have a serious communication problem. Everything we say sounds like spears.”

Yet Monday, he tweeted:

"@civilwarcometh: @BrandonMArms @RedNationRising I'm past impeachment. It's time to arrest and hang him high. http://www.commieblaster.com/ " Agreed

When a Republican candidate from a neighboring district questioned Black’s assertion, he doubled-down, comparing Obama to Benedict Arnold:

Chris Latvala @ChrisLatvala

@JoshuaBlack2014 you aren't seriously calling for the killing of Obama are you? I know you are crazy but good heavens.U R an embarrassment

Joshua Black 2014 @JoshuaBlack2014

@ChrisLatvala Execution is the appropriate punishment for traitors. #BenedictArnold #ReadAmericanHistory #criminalpoliticians

In subsequent tweets, Black clarified that Obama should first be convicted of treason by the U.S. Senate and jury. He also later issued an apology — for slandering Benedict Arnold.

In a Facebook post Monday evening, Black explained that he believes Obama should be prosecuted for his using drone strikes to kill Anwar al-Awlaki and his teenage son.

Pinellas Republican Chairman Michael Guju told the Tampa Bay Times that Black’s comments were “wholly unacceptable and unduly provocative.”

Black has also advocated for state nullification of federal laws, elimination of the Federal Reserve, and an end to all public welfare programs.