Politics can feel like an exclusive affair. You’re either completely devoted, or you’re not doing enough. Take choosing your presidential candidate: Bernie or Hillary? (Or Trump or Cruz or Rubio?) It’s not an easy choice until you’re truly satisfied with your research, chasing down every misgiving you have about your selection. By that time, you’ll have spent so much time thinking about it, you’ll have gained 20 pounds because you couldn’t exercise, you’ll have four books to catch up on because you couldn’t do your reading and you’ll have to schedule a meal with all of your friends that you couldn’t see. Along the way, you might realize some questions have no answers and that a ton of it is bullshit. So instead you go on with your life and resort to having opinions based on a general attitude. You’d lose a debate to anyone well versed in politics no matter how wrong you think they are, but the cost of winning — hours and hours of research — is too high. But this still feels wrong. Injustice dimly stares at you all the time. You need to be jolted into righteousness, and feel like it’s worth it. If you happen to work at the Yale Medical Library, that shock is waiting for you in the first hallway in the form of posters, the exhibit “Contra Cocaine and Other Works by Robbie Conal, Guerrilla Artist.”

There are only six posters, three of which show the same Contra Cocaine image, but it’s for the best: Anything more would overwhelm and eventually numb you. These are designed to hit hard and fast, leaving you in joyful indignation after a glance. Conal’s attitude is gleeful, righteous hatred. He takes an abominable figure, makes it grotesque and pairs it with a snappy message. It’s clean and it’s effective.

The poster featured in the title refers to the corruption and wretchedness of the Contra rebels in Nicaragua in the ’80s. This group, which claimed to have a right to governance, trafficked cocaine. Meanwhile, in the U.S., the Reagan administration continued to fund the rebels even after Congress passed a law banning such activity. Some of this money came from selling arms to Iran. This is absolute moral depravity. Imagine, at this time Nancy Reagan was expounding her “Just Say No” campaign!

Conal responds to this evil perfectly. So, we see a skeleton that is horrifying in its ghostliness, rendered perfectly in acrylic, dressed up in a suit against a “heroic” camo background. There are subtleties, such as the possible Grateful Dead perversion and the way the poster could also be read as simply antidrug, but its power is its immediate thrust. It activates your inner anger and hate and all the world’s problems. In fact, as the two decorated versions of the poster show, its simplicity is its power. The two others are decorated with glitter and acrylic. It’s attractive in a funny Halloween way, but its seductively crass beauty obscures the political message.

These posters are powerful because of their brash righteousness. My favorite is the Contra Cocaine poster because of its terrible backstory, but my second favorite features a grotesque portrait of former Chief Justice Rehnquist with the words, “Gag me with a coat hanger/Use your voice! Vote for Choice!” It’s a funny play on the gag rule upheld under Rehnquist where health care professionals in publicly funded family planning clinics were prohibited from providing information on abortion even when asked to do so. The clever wordplay against Rehnquist is a delicious kind of vengeance, but it also makes me uneasy. Is it OK to gag him, really? This morally ambiguous realm is Conal’s wellspring.

Comeuppance is great, but Conal’s work suggests that excessive vengeance can be more fun. With him, politics is not a burden. He calls himself a guerilla artist, recruiting people to his army. Every so often, his soldiers come together and plaster the entire city with posters in the middle of the night. Hearing him talk about it, it’s a party: “I have no idea no idea how effective we were in raising public awareness,” Conal once said of the Contra Cocaine poster. “But the poster committee had a blast!” I’m sure I would have.