President Trump can, on occasion, be unpredictable, but his approval numbers aren't.

He's the only commander-in-chief in the polling era never to never cross the 50 percent threshold, CNBC reports. His Gallup Poll peak is 46 percent and his low his 35 percent, good for an average of 40 percent to date; in Gallup's latest poll, he's right there again with a 39 percent approval rating. The consistency is not inconsequential when considering Trump's long-term electoral prospects, the Century Foundation's Ruy Teixeira told CNBC.

In 2018, just before the Republicans lost control of the House in the mid-term elections, Trump was at his normal 40 percent Gallup approval rating, while 54 percent of those surveyed disapproved of his performance. He's only budged slightly since then — and in the wrong direction, to boot. CNBC's John Hardwood notes that when former Presidents Bill Clinton and Barack Obama were routed by Republicans in the 1994 and 2010 midterms, respectively, they bounced back in their approval polls before winning re-election in 1996 and 2012.

Vegas oddsmakers still have Trump as the favorite in 2020, perhaps because Obama and Clinton were able to shake off those defeats to gain a second term. But Trump does not appear to be making up the ground his predecessors did to recapture the electorate.

Trump’s standing in Gallup poll just before losing House in 2018 mid-terms: 40% approve, 54% disapprove



now: 39% approve, 57% disapprove



presidents recover from mid-term defeats by adjusting



but Trump doesn’t adjust and his numbers barely movehttps://t.co/EOoWrl2xfX — John Harwood (@JohnJHarwood) September 10, 2019

Of course, polls have not recently proven themselves to be the ultimate litmus test for determining presidential elections. Read more at CNBC. Tim O'Donnell