One can’t run for office and support one of the other candidates. IMO His entire reason for running was to beat the Rats at their own game. The party often encourages a third candidate to divide the supporters of their opposition.
That’s how Newt was defeated and how he helped organize Trumps opposition. They encourage people to run that have no desire to hold office. The entire purpose of their candidacy is to divide their opposition’s base. Ask JEB how it feels! Newt paid back the Bush family bigly.