I don't think it's exactly a secret that many GOP Senators have had private concerns about Trump's behavior and actions since he first took office. The problem is that virtually none of them, except for McCain (and maybe Romney once or twice), have had the guts to actually call out Trump or oppose him in any meaningful way, out of a total fear of his response and that of his base, which is also their base. The most we have gotten are some "I'm so concerned" furrowed brows from Collins and maybe one or two others. In the end, though, they've always fallen in line. IMO, the only reason they're hinting that they might, just might speak up now is because his polling numbers are looking bad, and there's growing concern in the GOP high command that he may drag down their Senate candidates this year and cost them the Senate as well as the White House. If his polling numbers improve, my guess is that even these bare hints of some newfound independence will quickly vanish.