It seems to me that characterizing Trump as starting to "spook the left" is the wrong characterization especially given the two examples cited by PowerLine blog. IMO, all David Brooks and Willie Brown are doing is trying to look at Trump (and some of his accomplishments) in an objective way. Brooks noted some of Trump's foreign policy achievements while Brown cited "the jobs growth reports, the North Korea summit and the steady economy".
I don't think the left is spooked, but at least a couple of them seem to be trying to be objective IMO. I wish everyone would try and be more objective, and by everyone, I mean everyone: left, right, NTs, and ETs.