Danton is about democracy, communism, and other tools of oppression. The film belongs to a subgenre of the historical drama whose main thesis is that everything old is new again: Danton is not meant to highlight a past historical event, but to illuminate contemporary politics (technically, all historical works should strive for this goal, but Danton and its like are designed with a specific contemporary issue in mind, rather than generally delivering a timeless lesson). Wajda has apparently denied that the film was a metaphor for modern Poland, but the evidence seems beyond doubt. Along with the simple fact that Wajda chose to make the film at this time, there are other clues: he changed the sympathies of the original Communist-slanted version of the play from Robespierre to Danton, and - most importantly - he cast French actors as Danton and his people and Polish actors as Robespierre and his people. (By the way, this makes for some brutal dubbing, which you'll just have to pretend isn't happening by focusing intently on the subtitles.)
Nearly 30 years later, the politics of the film remain scarily relevant in post-9/11 America. With two successive presidents from different sides of the ideological spectrum embracing torture, supposedly "targeted" bombings, and civil liberties violations which verge on the unprecedented (including the legalization of assassinating American citizens) - not to mention the continued acceptance of the illegal machinations of Wall Street and the thoughtless support for corporations over individuals - the question of democracy vs. corrupt oligarchy is just as relevant in today's USA as it was to Wajda's Poland in the early 80s, even if the impact of the current philosophical crises are not felt as directly by the average American as they were by the average French person in the late 18th century or the average Eastern European person in the late 20th. (This is, of course, by design, as government has become more sophisticated in its ability to conduct itself in totalitarian ways without ruffling the feathers of the middle masses necessary for a true upheaval - a process that might be the true unsung genius of the political system in America.) All of this means the film plays as viscerally and razor-sharp as it did in the early 80s.
I loved all three films in Wajda's war trilogy, so I wasn't especially surprised that I loved this film. What was a pleasant surprise, however, was Gerard Depardieu's performance as Danton. The actor has given memorable performances before, though his American films have been almost universally horrible (except of course My Father the Hero). But his turn as the titular character is obviously essential to the film's success, and he pulls it off wonderfully, most notably perhaps in the key scene where he confronts Robespierre in person and offers him food and drink before cooly getting down to business. Depardieu manages to give Danton the heft and charisma to be a powerful presence, but he sticks him with the vanity and narcissism that makes his character much more complex and realistic. The script itself only hints at this complexity (Robespierre is the livelier figure on the page, which makes sense since he is the true protagonist of the film), but Depardieu's performance wrings it out of his best moments with natural ease.
Danton is a warning to the people. While its message cannot be misconstrued, the skill of Wajda's direction and the film's performances make it far more than a message film. It turns out after all to be one of those timeless explorations of the world's greatest challenge, a society answerable to the people that delivers safety and justice, freedom and protection from restriction, sacred ideals and broad tolerance, all in equal measures. Art isn't meant to give easy answers to this challenge, merely to illuminate the necessity of the pursuit of those answers, something Danton does beautifully.