1) Military deployments can be ordered by the President of the United States, the Commander-in-Chief of the Armed Forces, for up to 60 days (I may have this # off...it's early and I'm pre-caffeine) before the approval of Congress is required. This is necessary especially in times of emergency when an imminent threat exists to the nation's land and peoples. After this time, the approval of Congress is indeed necessary in order to declare war and continue it.
If you're really interested, I'll go dig out where this is Constitutionally, but I believe it's an Article 2 Presidential power.
[edit]The '60 days' is, I believe, set in Supreme Court precedent or federal law. The power of the President as Commander-in-Chief is set in Article 2, Section 2, Part a. Congress's power to declare war and to provide for the support of the armed forces is in Article 1, Section 8, Parts k-p. For more information, find the War Powers Act of 1973.[/edit]
As a side note, Senate is a part of Congress, as the House of Representatives is.
2) Considering the current Supreme Court stance on capital punishment and the States'/public opinion on it, it is doubtful if this could possibly pass. Even if it did, it might become about as successful as the 18th Amendment.
~Ladi