The story
Compare if only the tsar knew, German wenn das der Führer wüsste. Suggests that, if only the tsar were aware of the injustices of his bad boyars, he would immediately rectify the problems.
Etymology from Wiktionary, CC BY-SA 4.0.
good tsar, bad boyars
Today it means: an ideology that attributes good outcomes to the tsar, and bad outcomes to his inferior ministers (boyars). Full definition →