Texas Monthly has this article about the Forward Party, by Senior Editor Michael Hardy.
The article says that Ross Perot may have caused the election of Bill Clinton in 1992, and that Jill Stein may have caused the election of Donald Trump in 2016. Exit polls from both elections rebut this idea. Furthermore, in 1992, during the period July through September, when Perot was not a candidate, the polls consistently showed that Clinton was going to defeat President George H. W. Bush. Thanks to Fairvote for the link.