it does raise the question of how much is too much?
It's only too much if it hurts the cause of protecting America from the right.
I see the culture wars in the States as a cold war, with the conservatives having no compunctions or principles apart from a quest for power by any means possible. They are not fellow anything, just enemies of democracy, the rule of law, the middle class, and church-state separation. That is, they are enemies of America.
They are not restrained by temperance or forbearance. There is nothing they consider unethical or off the table. There is no longer a shared vision or shared values with such people.
In the light of that, my answer is the same as it would have been had I been asked what is too much with the Soviets? What tactic could possibly be unethical dealing with such a government? Is it possible to be unfair to them? Treat them like the US treated Castro. Or Hussain. Or bin Laden - all enemies of the United States.
I say no, and no here as well. I have different values for those with whom I share those values than I do for these people. I wouldn't lie to an honest person, but I wouldn't hesitate to lie to these people. Although this was not that, I would support a false flag operation if it weakened the enemy and provided a tactical advantage to those attempting to protect democracy and the middle class from these people.
Anything that helps defeat Younkin is fair game, including tying him to Trump and his fascist base, which is what the Lincoln Project did so well in 2020.