Serious question: When, aside from a few noteworthy exceptions, have our presidents/kings/emperors/prime ministers ever been ANYTHING OTHER THAN flawed human beings -- sometimes with quite grievous shortcomings and even sins?
Serious [obvious] answer: Never.
So Catholics have always been aloof from national politics, …
"Assumes facts not in evidence." Who advocated "always"* being aloof from national politics? Not I.
*Didn't you just accuse someone of making a straw man argument? :-)
…which is nothing more or less than concern for one's country and its well-being?
National politics = concern for one's country and its well-being? No. Well-ordered patriotism = concern for one's country and its well-being. National politics is a process—in the case of the jUSA, a deeply flawed process steeped in some disordered fundamentals (e.g., separation of Church and State, just authority bubbles up from below, etc.).
What if invasion by a hostile force like the Muslims were in play?
It depends. Besides, the idea of a military invasion by Muslims is, in my estimate, too far-fetched to consider seriously.
What if occupation by a hostile force like the SoS were in play? Ooops, we already have that and Trump abets it further.
Wouldn't that compel Catholics to "get involved" or support their sovereign, even if he were flawed and had some public sins?
Which "he"? Trump? Or some generic POTjUS?
Consider your key reason for supporting Trump. Would abortion decline in a Muslim-ruled USA?
Even before the rise of Fɾҽҽmαsσɳɾყ, our Kings and Queens have had serious flaws. And yet -- we pray for them, the Church has us pray for them, for they are the secular power and they receive authority from God, from whom all authority and paternity flows.
Agreed.
As for voting in democracies, I didn't think we were voting for sainthood. Or else the office of president would have been empty for what, the past 240 years?
As for voting in democracies, I don't think the lesser of two nearly equivalent evils is enough reason to vote.
N.B., Though I had serious reservations, I did vote for Trump in 2016. I chose to vote for a bad man rather than a [possibly] possessed female. There was much speculation about the videos of Hillary being evidence of neurological disorder. In my estimation, I thought the videos were more supportive of imperfect possession than a neurological disorder.