Cicero says no:
It must, therefore, be enjoined upon good men that if by any chance they should inadvisedly fall into friendships of this kind, they must not think themselves so bound that they cannot withdraw from friends who are sinning in some important matter of public concern; for wicked men, on the other hand, a penalty must be enacted, and assuredly it will not be lighter for the followers than for the leaders in treason. Who was more eminent in Greece than Themistocles, who more powerful? But he, after having saved Greece from slavery by his leadership in the war with Persia, and after having been banished because of his unpopularity, would not submit to the injustice of an ungrateful country, as he was in duty bound to do: he did the same thing that Coriolanus had done among our people twenty years before. Not one single supporter could be found to aid these men against their country; therefore, each took his own life.Hence such alliances of wicked men not only should not be protected by a plea of friendship, but rather they should be visited with summary punishment of the severest kind, so that no one may think it permissible to follow even a friend when waging war against his country. And yet this very thing, considering the course affairs have begun to take, will probably happen at some future time; as for me, I am no less concerned for what the condition of the commonwealth will be after my death, than I am for its condition to‑day.
Therefore let this be ordained as the first law of friendship: Ask of friends only what is honourable; do for friends only what is honourable and without even waiting to be asked; let zeal be ever present, but hesitation absent; dare to give true advice with all frankness; in friendship let the influence of friends who are wise counsellors be paramount, and let that influence be employed in advising, not only with frankness, but, if the occasion demands, even with sternness, and let the advice be followed when given.
[Marcus Tullius Cicero, On Friendship (De Amicitia) Loeb Classics Library pp.156-7]