To expand on your point: It wasn't Russia who invaded Czechoslovakia in 1968. It was entire Warsaw pact. Or, almost entire. There was one country, that didn't take part: Romania. Out of the entire Warsaw pact only Ceaușescu's Romania had the backbone to not invade. Others, like GDR, Poland, Hungary, took their part voluntarily. (That's nothing new: Poland and Hungary attacked the rump Czechoslovakia in 1938 too. That's just expanding your second paragraph).

There is yet another twist - even for USSR, it wasn't Russia itself. It was USSR, which was comprised of many more countries at the time. The units that were in Czechoslovakia were Ukrainians. And before there are arguments, that they were commanded from Moscow, the head honcho at the time was Brezhnev, from Ukraine.