No you can't. This is why we are living in "post-truth". Meaning it's not truth anymore.
You are right in that either one can win, but only one can be true.
Of course both sides can put forth true arguments in a political debate. I'm having a hard time coming up with a real world example, both because I don't want to push buttons that force you down a knee-jerk path on the button I push when I don't really care about it, and because we're really not used to seeing honest debates in the political arena.
But when society faces a decision A or B, each side can completely honestly tout the benefits of their decision and the costs of the other decision, both of which will exist. And God Almighty could come down from on high and hand us the exact, true, and full consequences of each decision, and those who benefit from one decision can completely honestly argue in its favor while those who may not benefit could completely honestly argue against it, which could be completely different sets of people for each decision. (There's almost never a decision that benefits everybody, even before we get into questions like relative amounts of benefit, or how society as a whole benefits.)
An argument containing elements of truth, or even somehow consisting entirely of truth, does not make it correct, because it still won't be the complete truth, which may well contain a superior argument for a different decision in it. But we don't have access to complete truth.
I was stating that two opposing arguments can't both be true, because then there is no truth.
We are not talking about some rhetorical analysis of language and I never meant it in that sense which the context of this discussion should have made clear. If not then I am remedying that now.
I would urge you to give me examples in politics which can't have two different political outcomes both potentially true.
Climate change.
