"Right to die" is just a slogan. No civil right to commit suicide exists in any social compact.
The issue of legalizing physician-assisted suicide doesn't fall cleanly along liberal-conservative lines. However, it's fair to say that most social conservatives ardently oppose assisted suicide, while a clear majority on the political left support legalization. That's the case in Massachusetts where Question 2 is on November's ballot, and according to recent polling is very likely to pass.
I am an outlier, in that I am a registered Democrat and progressive, as well as a physician who has cared for people with life-threatening conditions for more than three decades. I support universal health care, voting rights, disability rights, women's rights, Planned Parenthood, gay marriage, alternative energy, and gun control. I yearn to see an end to the war on drugs and the war in Afghanistan. And, I am convinced that legalization of physician-assisted suicide is something my fellow progressives should fear and loathe.
When cast as a rights issue, it's hard for progressives to resist. But "the right to die" is just a slogan. No civil right to commit suicide exists in any social compact. Human beings have a biologically imposed obligation to die; and, as Jean Paul Sartre reminded us, suicide is always an option. However, even if a civic right to suicide did exist, suicide and assisted suicide are very different things. Suicide might be a purely private act; but physician-assisted suicide involves two people, one of whom is trained, certified, licensed, and compensated by society.