Alabama 

In the case of Alabama, Trump actually rescind an endorsement and that made quite the splash. Trump rescinded his endorsement of Alabama Senate candidate Mo Brooks, and Brooks, who was previously in the lead by huge margins, has since completely fallen in polls. 

In a statement, Trump said “very sad but, since he decided to go in another direction, so have I, and I am hereby withdrawing my Endorsement of Mo Brooks for the Senate.”