As for your question about having to declare war first
The Executive Branch also has Emergency Powers to make decisions if the President deems it a threat to our national interests and I would think that may apply in not having to formally declare war.
I will have to research that more but it makes sense using the Emergency Powers gives the President more authority
This is what I found in part....
In modern times, however, Presidents have used military force without formal declarations or express consent from Congress on multiple occasions. For example, President Truman ordered U.S. forces into combat in Korea; President Reagan ordered the use of military force in, among other places, Libya, Grenada and Lebanon; President George H.W. Bush directed an invasion of Panama to topple the government of Manual Noriega; and President Obama used air strikes to support the ouster of Muammar Qaddafi in Libya. Some commentators argue that, whatever the original meaning of the Declare War Clause, these episodes (among others) establish a modern practice that allows the President considerable independent power to use military force.
Second, Presidents are thought to have independent authority to use military force in response to attacks on the United States. At the 1787 Philadelphia convention, Madison described the Declare War Clause as leaving the President with authority to repel sudden attacks. The scope of this power is sharply contested, however. Some commentators think it includes defense against attacks on U.S. citizens or forces abroad, in addition to attacks on U.S. territory; some would extend it to attacks on U.S. allies or U.S. interests, defined broadly. Some commentators think it includes defense against threats as well as actual attacks. Some think it allows the President not only to take defensive measures but also to use offensive force against attackers.
Third, Presidents may use other constitutional powers – principally the commander-in-chief power – to deploy U.S. forces in situations that do not amount to war. For example, President Bush’s deployment of troops to Saudi Arabia after Iraq’s invasion of Kuwait in 1990 probably did not implicate the declare war clause because at that point the troops were not involved in combat. Similarly, deployment of U.S. troops as peacekeepers (as President Clinton did in Bosnia) likely does not involve the United States in war and thus does not require Congress’s approval under the Declare War Clause. More controversially, it is claimed that involvement in low-level hostilities may not rise to the level of war in the constitutional sense. President Obama argued on this ground that U.S. participation in the bombing campaign in Libya in 2011 did not require Congress’s authorization. However, this position is strongly disputed by other commentators. A related argument, also controversial, is that using force against non-state actors such as terrorist organizations does not amount to war, and thus does not implicate the Declare War Clause.
The law of the Declare War Clause is unsettled in part because there have been very few judicial decisions interpreting it. In the
Prize Cases in 1863, the Supreme Court upheld as a defensive measure President Lincoln’s blockade of the southern states following their attack on Fort Sumter, but was ambiguous as to whether the authority for the blockade came from Article II, from specific statutes Congress had passed in 1795 and 1807, or some combination of both. And in dicta, the Court noted that the President could not begin hostilities without Congress’s approval. Earlier cases, such as
Bas v. Tingy (1800), referred generally to Congress’s broad powers over warmaking without giving specific guidance on the President’s power. But in modern times, courts have generally avoided deciding war-initiation cases on the merits, based on rules that limit what types of disputes courts can resolve, such as standing or the political question doctrine. As a result, the precise contours and implications of the Declare War Clause remain unresolved today—leaving resolution of disputes over particular uses of force by the President to the political process.
Interpretations of Declare War Clause by constitutional scholars
constitutioncenter.org
www.usconstitution.net
