The English never thought much of the Polish-Lithuanian Sejm. In 1598 John Peyton, identified recently as the author of an extensive report on the Polish-Lithuanian Commonwealth prepared for King James, observed that the Sejm was faction-ridden, and marveled that ‘according to the auncient custome of the Northern nations, whose power is in their fyste, they come into the Senate armed’.
John Peyton expressed surprise that ‘considering the deadly feude of greate familyes and the virulent inveighing against them they comme not to strokes to the manifeste ruine of the state’. He scoffed at the slowness of deliberations on account of ‘tedious orations in both howses’ — the Senate and the Chamber of Envoys — and that, on account of the principle of unanimity that governed debate, ‘matters for the publike goode (especially yf they bringe with them any charge) are not very easeley concluded’.
By 1700, when the notorious Liberum Veto — the logical extension of the principle of unanimity, by which the objection of one envoy could not only block legislation, but could break the Sejm — had become institutionalized, the Sejm was a laughingstock.
Yet the opportunity to be King of Poland was a consideration for the exiled James II. Louis XIV thought it an excellent solution to having his impoverished cousin camping near Paris permanently.
For more on Poland's form of (read lack of) democracy: