On Friday, Sen. Susan Collins (R) was in her home state of Maine, speaking at a chiefs of police conference, and fielding questions from reporters about her recent votes in support of Donald Trump during the presidential impeachment trial. Not surprisingly, the Senate Republican defended her decision, saying the evidence did not meet "the high bar" for removing a president from office.

But as the Portland Press Herald noted, she also touched on a related point.

[Collins] condemned the notion of retribution against witnesses who came forward. [...] She then added: "I obviously am not in favor of any kind of retribution against anyone who came forward with evidence."

It was just hours later when Trump, checking names off his enemies list, fired Ambassador Gordon Sondland, removed Lt. Col. Alexander Vindman from his White House job, and even ousted Vindman's brother, Lt. Col. Yevgeny Vindman, an Army officer who also worked on the National Security Council staff.

Yevgeny Vindman, who goes by Eugene, wasn't involved in any way with the president's Ukraine scandal, but he's Alexander Vindman's brother, so Trump apparently decided he had to go, too.

Get the msnbc newsletter. This site is protected by recaptcha

There is no mystery behind Trump's moves. He and his team didn't even bother with fig leaves or pretexts. On the contrary, from the White House's perspective, that would've been counter-productive: the point of the late-Friday maneuvers was to send an unmistakable signal about the president and his eagerness to retaliate against those who play by the rules.

Fernando Cutz, who was a top aide to then-White House National Security Adviser H.R. McMaster, told the Washington Post, "Every career official will tell you it's not just chilling but frightening. You're seeing things happen in an unprecedented way that even Nixon didn't do.... The broader message to career officials is that you can't speak up. Even if you see something illegal, something unethical, you can't speak up. That's the message the president wants to send."

There's little doubt that this assessment is true. One of the broader questions, though, is the degree to which congressional Republicans have heard that message, along with those who work in the administration.

As the dust settled on Trump's aggressive personnel moves, the Associated Press reported, "Senate Republicans, who just two days prior acquitted Trump of charges he abused his office, were silent Friday evening."

That remained true over the weekend, though the silence was briefly broken when Senate Judiciary Committee Chairman Lindsey Graham (R-S.C.) appeared on CBS's Face the Nation -- and defended Trump's firings.

According to multiple accounts, a handful of Senate Republicans had privately urged the president not to fire Sondland, but Trump appears to have ignored them, exacting revenge anyway.

And it's against this backdrop that we've heard nary a discouraging word from the GOP senators whose job ostensibly involves holding the White House accountable for abuses.

The prevailing emotion is fear. Republicans know it's wrong for Trump to retaliate against witnesses, but they're afraid to say so. Republicans knew witness testimony would've made the impeachment trial fairer, but they were afraid to say so. Republicans knew the evidence against the president made his guilt plain, they were afraid to say so.

If recent history is any guide, we may hear from Collins and some of her colleagues today, who'll express "concern" and "discomfort" with Trump's Friday-night firings. Some will wag their finger and ask politely that the president restrain from crossing more names off his enemies list. Others will furrow their brow, while asking not to be quoted on the record.

But each will effectively tell the White House that Trump can do as he pleases with impunity, confident in the knowledge that his terrified party won't even try to hold him accountable.

MORE: Today's Maddowblog