The former president's lawyers have, as they see it, an easy job.
Their job is not to disprove the Impeachment Managers' case. It's not even to sever the thoroughly proven and obviously authentic link between the former president and his scheme to get his very beautiful face up there on Mt. Rushmore, no, on the $100 bill. No: both!
No. Their job is to construct an alternate narrative out of whatever loose ends they can grab. It need not be leakproof or seamless, or even very clean. As long as it kind of hangs together like a narrative. It could have unicorns, for all that matters. It will be cover enough.
See, this is how it works in the Attention Age: the only power is in people's immediate attention. There's no time for thinking things through before everything tilts again, and the floor becomes a wall.
If the Republicans can construct some kind of a narrative they can all memorize, the impeachment will be converted into another story, and the two will cancel each other out.
At that point the Republicans will vote to acquit, and go home, because at that point neither story can hurt them anymore.
It doesn't matter if anybody believes them or not. They aren't going to choose between two narratives. You can do that if you want to. You'll only be choosing a side.