Fact Checker: Trump says he has the record for approval among Republicans. He doesn’t. - The Washington Post

This is one of those Trump claims that initially seemed too inconsequential to be worth a full-fledged fact check. So when he first asserted on Twitter on July 10, 2018, that he was “the most popular Republican in the history of the party,” we tossed it into our database of Trump’s false or misleading claims.
https://www.washingtonpost.com/politics/2019/06/05/trump-says-he-has-all-time-record-approval-among-republicans-he-ranks-sixth/