We, as Americans should respect the OFFICE of the POTUS. All should agree that it is for the honor of the entire nation that its leader is honored and respected. Anyone who has ever been to D.C. cannot ignore the feeling of malchus emanating from those austere edifices.
Thus, our president (as well as all public officials) should be regarded with respect, even if it is undeserved. It is not his as a person whom we respect, but rather the chair which he occupies. This should apply even if he is impeached by one body of congress, as long as he has the job.
That said, the president is not divine, and his mistakes and shortcomings should be called out, either in a respectful manner, or in private.
I should add that if your complaint is just for the sake of grumbling, better hold it. You will have gained nothing, and the wisest of all men advised: “Even in your [private] chamber, a king you should not curse, for the bird of the heavens will carry the sound, a winged one will tell the matter.” (Translation mine.)
This applies to all Americans. As for Yidden, it’s best to lie low in galus (which includes the gola on our sacred land). “Hatzpinu atzmichem ad sheyaavor olamo…”