Jonah, on senate action, I don’t think the legally significant issue is so much whether the president sends a signed treaty to the senate for its consideration versus whether the senate unilaterally takes action on a treaty the president has signed but declined to send. It’s what happens after senate action, whether requested by the president or not.
It is a common misconception that the senate ratifies treaties. The senate does not ratify a treaty. Under the constitution, the senate’s function is to consent to a treaty (or decline to do so). It is the president who ratifies. That is, if the senate consents to a treaty by the required two-thirds vote, that act does not operate to make the treaty the law of the land. The president still has to ratify.
The president cannot ratify without senate consent, but the senate’s consent does not create an obligation on the president’s part to ratify. Moreover, presidents can unilaterally pull us out of treaties — as Bush, for example, did with the ABM treaty and, more recently, with the Optional Protocol to the Treaty on Consular Notification. If ratification were a legislative act, I don’t believe a president could reverse it unilaterally — it would have to be done by statute. The president has this power, however, because ratification is an executive act.