President Donald Trump had nothing but kind words to say about Rep. Haley Stevens after she dramatically swung her support to Republican Mike Rogers in his Senate seat campaign.

Speaking with reporters after news broke, Trump said he wanted to call and thank her, remarking ... "She did the right thing."

Claiming that he'd love to have her join the Republican Party ... Trump called the Michigan lawmaker very brave after a stunning turn of events where she reached across the aisle to support her former opponent.

DJT, who is closely aligned with Rogers, added ... "I don't know her, I've never met her, but I have great respect for her."

Earlier today, the Prez gave us a preview of his opinion on the Stevens move that rocked the whole Hill ... calling her a "highly respected Democrat."

We reported earlier ... Stevens abandoned her support for Democratic candidate Abdul El-Sayed -- who beat her in the party's primary.

In the wake of her announcement, both her chief of staff and communications director reportedly resigned.

Stevens' fiancé Jason Turkish joined "TMZ Live" Friday and claimed that Haley might drop her support for El-Sayed over his ads she felt were anti-Semitic.