If we believe there is criminal justification for pulling years of tax returns, I suggest we start with Diane Feinstein, who made her fortune climbing into bed with the Chicom govt and who facilitated Chinese espionage against the US govt for decades...
From there we can move to Hillary Clinton, already under investigation still (last reportedly) for influence peddling, who took millions from the Russians, whose husband took $500k from the KGB Bank before meeting with Putin, who paid foreign spies and Russians for their help in trying to in the 2016 election...