Sen. Robert Hartwell sat alone in his committee room this morning, poring intently over “Robert Baxter versus the state of Montana.”

The 2009 case went all the way to the Montana Supreme Court, where judges weighed the legal implications of allowing doctors to hasten the deaths of their terminally ill patients. The Supreme Court ultimately said it could find “find no indication in Montana law that physician aid in dying provided to terminally ill, mentally competent adult patients is against public policy.”

Hartwell and the rest of the Senate will decide later today whether to enshrine in Vermont law a citizen’s right to request a lethal dose of medication from their doctor.

The drama surrounding today’s vote stems in part from the uncertainty of its outcome. Hartwell, a Bennington County Democrat, was among the four lawmakers who had yet to announce publicly where they stand.

Earlier today, the ranks of the undecideds shrank to three when Sen. John Rodgers announced that he’ll be voting in favor of the legislation.

The Senate chamber is packed today with supporters and opponents of a controversial legislation that promises to engender an inspired floor debate.

We’ll bring you updates on this historic debate throughout the morning and afternoon, and have the vote to you as soon as it’s counted.