Yes, it was unfortunate, and tragic, but this was not an "unnecessary or unwarranted" tit for tat. Wasn't it Biden who specifically criticized the President for inaction when the Iranians shot down that unmanned drone? Would Biden have cheered our lobbing of a retaliatory missile? Of course not - when it comes to Trump, he's damned if he does and damned if he doesn't.
The President didn't engage in tit for tat then, but following the assault on the U.S. Embassy, and the death of an American citizen hit by militia fire directed by the Iranians, he decided upon an appropriate and proportionate response - and fired a kill shot at the most dangerous terrorist in the last 30 years. Tit for tat? Sure. But it was also an extraordinary demonstration of American intelligence and military skill, and reinforced our policy of deterrence as an alternative to the larger destruction caused by wars launched by foes seeking to exploit our weakness and lack of resolve.
That's what we have to look forward to if the Dems regain the White House - endless poking of a weak and distracted bear.