He died in 1955, so I doubt he was familiar with 'tankie' being a thing.

Einstein's opinions on the Bolsheviks changed with time. In 1925, he criticized them for not having a 'well-regulated system of government' and called their rule a 'regime of terror and a tragedy in human history'. He later adopted a more balanced view, criticizing their methods but praising their goals, demonstrated by his 1929 remark on Vladimir Lenin: "I honor Lenin as a man who completely sacrificed himself and devoted all his energy to the realization of social justice. I do not consider his methods practical, but one thing is certain: men of his type are the guardians and restorers of the conscience of humanity."[55][56] Rowe translates the beginning of the second sentence as "I do not find his methods advisable".[57]

In 1949 Einstein stated "The achievement of socialism requires the solution of some extremely difficult socio-political problems: how is it possible, in view of the far-reaching centralization of political and economic power, to prevent bureaucracy from becoming all-powerful and overweening? How can the rights of the individual be protected and therewith a democratic counterweight to the power of bureaucracy be assured?".[58]

In the twenties, when no dictatorships existed, I advocated that refusing to go to war would make war improper. But as soon as coercive conditions appeared in certain nations, I felt that it would weaken the less aggressive nations vis-à-vis the more aggressive ones.

In September 1942, in a private letter to Princeton University president, Einstein criticized the U.S. for not doing enough to fight Nazi Germany. He argued that "If Hitler were not a lunatic he could easily have avoided the hostility of the Western powers" if not for his threats of world domination.

Most of us are not neutral in feeling, but, as human beings, we have to remember that, if the issues between East and West are to be decided in any manner that can give any possible satisfaction to anybody, whether Communist or anti-Communist, whether Asian or European or American, whether White or Black, then these issues must not be decided by war. We should wish this to be understood, both in the East and in the West.

There lies before us, if we choose, continual progress in happiness, knowledge, and wisdom. Shall we, instead, choose death, because we cannot forget our quarrels? We appeal as human beings to human beings: Remember your humanity, and forget the rest. If you can do so, the way lies open to a new Paradise; if you cannot, there lies before you the risk of universal death.

He was probably more of dem soc then an ML, but I think if he had lived through the 60s he would have been pretty close to Parenti after seeing how things unfolded in the geo-political landscape.