In An Enemy of the People, Dr. Thomas Stockmann is chief medical officer at The Baths, a health resort that is soon to open. Though he first conceived the idea of developing this resort, his older brother, Peter, the mayor of the town, had the business sense and political connections to put it into effect. Ibsen uses the contrast between the two brothers to establish the ideological framework of the play: Thomas is a liberal but impractical idealist; the ultraconservative Peter is motivated chiefly by self-interest and what he calls “the good of the community.” Dr. Stockmann’s home is a haven for people with liberal ideas: Billing and Hovstad, who edit the town’s liberal newspaper; Horster, an open-minded sea captain; and Thomas Stockmann’s freethinking daughter, Petra, a schoolteacher. Petra is the first character to raise what is to become the major theme in the play, the “life-lie.” When she complains that, at school, she is forced to teach children to believe in lies, Captain Horster encourages her to found a school where children will learn the truth.

The crucial issue in the play emerges when Dr. Stockmann receives a laboratory report confirming his suspicions that the water supply for The Baths is polluted. Jubilant that he has detected the contamination in time to prevent a disastrous epidemic, all the liberals offer their support and declare him a public hero. Peter Stockmann, however, intends to discredit his brother, because the enormous costs of reconstructing the water system spells financial ruin for the investors and, ultimately, for the whole town. Because he has the liberal press and the majority on his side, and, above all, because he is right, Thomas is confident of victory. The battle lines are quickly drawn, but the motives on both sides are mixed. Thomas Stockmann’s wife, Katherine, sees the impending fight as a threat to the security of her family. The mayor fears financial ruin and the erosion of his political power. Hovstad is a spineless political opportunist who will espouse any cause that promises to increase his power. Katherine’s surrogate father, Morten Kiil, wants revenge for having been voted off the town council. Because Thomas Stockmann and Petra are the only combatants free of self-interest, it proves easy for the mayor to swing the entire community to his side.

Unable to get his message across through the press, Thomas Stockmann calls a public meeting in Captain Horster’s house, where he intends to expose the fact that the whole town’s prosperity is rooted in a lie. His opponents take charge of the meeting, however, and rule all discussion of The Baths out of order. Goaded to fury, he abandons his intended subject and develops the symbolic significance of the situation: The town’s spiritual sources are polluted, and the whole civic community is built over a cesspool of lies. The authorities may be stupid and inflexible, but the worst enemy of truth and freedom is the majority. He launches into a diatribe against the whole notion of a democratic society. The majority is always wrong, he claims, because most people are fools, too lazy to think for themselves and therefore easily led by demagogues. Truth is relative and always changing; by the time that truths filter down to the majority, they are so outdated that they can hardly be distinguished from lies. One such lie is that the common herd has the same right to criticize, govern, and counsel as the few intellectuals. The elitism and incipient racism of his remarks about the relation between class and intelligence so incense the crowd that he is voted “an enemy of the people.”

The hostility of the mob does not stop with a vote of censure; the Stockmann family is assaulted on every front. The mayor and his supporters visit Thomas Stockmann and try to appeal to his self-interest in the hope of getting him to retract his report on the pollution at The Baths. The final test comes when old Morten Kiil informs him that all the money that he would have left to Katherine’s children is invested in The Baths and will be lost unless he says he was mistaken about the contamination. All these threats to his integrity convince Thomas Stockmann to abandon his plan to take his family to the United States. He realizes that he must stay in Norway and fight. He and Petra vow to open a school in Horster’s house, where they will try to train the “mongrels” to become decent and independent-minded people.

One problem that arises in interpreting this play stems from the disparity between Thomas Stockmann’s facts, which are correct, and his opinions, some of which are indeed questionable. He is frequently ridiculous, and his elitism (his talk of “mongrel” people) clashes sharply with the progressive views that he claims to cherish. Ibsen apparently undermines his protagonist in this manner because there is no reasonable spokesman for the other points of view. In adapting this play for the American stage, American playwright Arthur Miller eliminated Thomas Stockmann’s disagreeable or ridiculous traits, as well as his “fascistic” opinions.