While it may prove to be true that there is nothing criminal about “colluding” with foreigners, a suggestion by the president or his advisers of some sort of collusion in Trump Tower could put Don Jr. legally sideways. That’s because Trump Jr., in his interview with the Senate Judiciary Committee, declared: “I did not collude with any foreign government and do not know of anyone who did.”

Don Jr. cannot now claim to have engaged in some sort of everybody-does-it noncriminal “collusion” without running afoul of 18 USC Section 1001, which, as Trump Jr. was warned, “makes it a crime to make any materially false, fictitious, or fraudulent statements or representations in the course of a congressional investigation.”

Similarly, President Trump has clung to his assertion that when it came to the Trump Tower meeting, “I did not know about it!” That is a snug fit with what Don Jr. said when asked by Senate investigators, “Did you inform your father about the meeting or the underlying offer prior to the meeting?” Trump Jr.’s response left no wiggle room: “No, I did not.” If Trump Sr. abandons his assertion he was out of the loop, Don Jr. is the one left holding the bag.