The House voted 152-38 Monday night to approve a key amendment to a Senate bill that would set up a government and medically regulated system in which marijuana would be grown, processed and dispensed, with a prescription, to the terminally ill and patients suffering from various diseases and ailments that they and their loved ones say cannot be treated by conventional medicine. The vote, along with several others on related amendments, united moderate and conservative Republicans with blue-dog and liberal Democrats — a scenario that seemed unthinkable just six months ago.