One measure of a President Donald Trump's plummeting popularity is how candidates likely to be on the 2018 ballot are positioning themselves.

Look no further than state Rep. Knute Buehler (R-Bend), a second-term incumbent widely believed to be eying a run for governor in 2018. (That could set up a possible rematch with Gov. Kate Brown, who beat him in the 2010 secretary of state's race.)

Buehler, an orthopedic surgeon, is pretty moderate—but today, he made sure Oregonians know precisely how he feels about the president.

"As a Republican, I feel a special obligation to speak-out against the actions of the President of my Party – even a candidate I didn't support," Buehler wrote in a Facebook post. "Being inexperienced, ill-tempered and even incompetent are not crimes, but impeding or obstructing justice is, so we need to fully understand what President Trump has done."

Earlier today, Buehler endorsed the appointment of a special counsel to review the president's possible ties to Russia.

"As an elected official – and a Republican – I am frequently asked my opinions about President Trump," Buehler continued.  "Almost daily. Frankly, commenting on President Trump could be a full-time job if I let it become one. Therefore, I try to keep my focus on my responsibilities as an Oregon state legislator and representing the people of Bend. But the current chaos surrounding the President requires me to speak my mind. In the end, it will be up to our federal officials of both parties to speak theirs. Because the future of the Presidency and our nation is at stake."

Buehler also celebrated news reports this afternoon that the federal Department of Justice named former FBI Director Robert Mueller as a special counsel for the Trump/Russia investigation.

"I just saw the news on the Mueller appointment," Buehler wrote this afternoon. "Very pleased. Now Congress needs to play its role too."