Of the myriad possible defenses of President Trump, Alan Dershowitz managed to make one of the worst available.
The rest of Trump’s legal team made the case that Trump wanted Ukraine to initiate investigations into the Bidens’ conduct during the Obama administration and whether the country had interfered with the 2016 election. Because the House refused to wait for witness subpoenas, Democrats haven’t been able to prove that Trump was actually calling for the Biden investigation to influence the 2020 election instead. So the Republican defense is one that defies instinct and was certainly not definitive, but it works. It tries to establish that Trump’s withholding of congressionally approved aid was intended to investigate corruption, however conspiratorial, rather than abuse his power for political gain.