Proposition 106 would let terminally ill patients take their own lives with medication prescribed by a physician. If it passes, Colorado would be the sixth state where this is legal, joining Oregon, Washington, California, Montana and Vermont.

The measure is modeled after Oregon’s first-in-the-nation law and has several key components. You must be a resident of Colorado, an adult 18 or older, and determined by two doctors to be “mentally capable” of making healthcare decisions. You must be making the choice voluntarily and must self-administer the doctor-prescribed drug, generally a sleeping medication called secobarbital.

Proponents include the group Compassion and Choices, which has raised nearly $5 million to try to pass the measure. They argue people should have the choice to end their lives as they choose, especially if they’re facing an agonizing, painful death.

Opponents have given more than $1 million to the No Assisted Suicide campaign. That includes the Archdiocese of Denver and Colorado Christian University. Both argue the measure is “fatally flawed,” beyond being morally wrong. They say doctors can make mistakes and that the measure won’t stop doctor shopping and won’t require a doctor to be present when a person dies. They also worry the measure would create a slippery slope potentially leading to euthanasia. In addition, some advocates for the disabled believe that under the measure insurance companies might deny coverage of lifesaving medical care in favor of end-of-life medications.

A “yes” vote means terminally ill patients would be able to end their lives with doctor-prescribed medication. A “no” vote would prevent Colorado from legalizing the practice.