- The US hasn't formally declared war since World War II
- A declaration of war grants the president certain emergency powers
Washington (CNN)Donald Trump is vowing to declare war against ISIS.
"We're going to declare war against ISIS. We have to wipe out ISIS," Trump said in an interview that aired on CBS's "60 Minutes" Sunday night.
The presumptive Republican nominee for president had previously pledged to ask Congress for a declaration of war immediately following Thursday's terrorist attack in Nice.
But given that the U.S. has been fighting ISIS for close to two years, what would that to do change things? Here are some answers.
Are we at war with ISIS already?
Technically, no. Article I, Section 8, of the U.S. Constitution says: "Congress shall have the power ... to declare War." It has not done so against ISIS.
The U.S has been conducting airstrikes for years and has sent trainers and Special Operations Forces to help combat the terror group.
But the U.S. hasn't formally declared war on ISIS -- or on anyone else since 1942, when Congress voted to do so against Nazi Germany allies Bulgaria, Hungary and Romania.
Modern U.S. conflicts have instead been governed by the War Powers Resolution of 1973. Passed in the wake of America's unpopular involvement in Vietnam, the act sought to limit the ability of the president to send U.S. troops into combat without Congress' approval.
"In an absence of a declaration of war," the resolution requires congressional notification and approval "whenever United States Armed Forces are introduced into hostilities" within 60 days of their deployment.
Recent military interventions in Afghanistan and Iraq met these legislative requirements by receiving Authorizations for the Use of Military Force, or AUMFs, passed by Congress in 2001 and 2002, respectively.
The administration and many in Congress believe the current fight against ISIS is authorized by the 2001 AUMF for the battle against the Taliban and al Qaeda because ISIS originated, in part, out of al Qaeda in Iraq.
How is a declaration of War distinct from an AUMF?
"There are big differences between a declaration of war and an AUMF," American University law professor Stephen Vladeck told CNN.
Vladeck, who specializes in national security law, said that a formal declaration of war by Congress would grant the president, as commander in chief, dozens of additional powers beyond dispatching troops to conduct military operations. These include allowing the detention and deportation of nationals and confiscation of property from the country with which the U.S. is at war.
In addition, authorizations of military force are specific legislation that Congress drafts that often can include considerable restrictions on the president's ability to operate in a conflict.
Since AUMFs are "much more tailored," as Vladeck put it, it can include limitations such as on the length of the conflict. "It's more specific about goals and limits."
Vladeck said that is the reason AUMF's are easier to move through Congress than formal declarations. Congress would rather spell out clear terms to the White House rather than give it a blank check.
Didn't the President try to get authorization for using force against ISIS?
Yes. In 2015, President Barack Obama asked Congress to formally authorize the use of military force against ISIS. Obama said he did so because even though he believes he has proper legal authority to go after ISIS without it from the 2001 AUMF, the President said he has been committed to seeking bipartisan support from lawmakers for the ISIS campaign.
However, some Republicans in Congress, while supportive of a new authorization, balked at his proposal because it would put limits on the use of ground troops in fighting ISIS that would limit his successor's ability to do so as well.
"I will not support efforts that impose undue restrictions on the U.S. military and make it harder to win," Republican House Majority Leader Kevin McCarthy said last year, indicating he would back a broader AUMF.
It's not the first time Obama has clashed with Congress over such a resolution. During the 2011 U.S. intervention in Libya, members of Congress, including Republican Sen. Rand Paul of Kentucky, accused the administration of violating the War Powers Resolution by not obtaining congressional authorization.
Trump's take sounds similar to possible Democratic VP pick Tim Kaine. Is it?
Yes and no.
Kaine, a Virginia senator and considered a leading candidate to be Clinton's vice presidential nominee, has pushed for a new AUMF and argued that the absence of new congressional action was undermining the fight against ISIS.
"I am deeply concerned about the legal basis for this war," Kaine told Secretary of Defense Ash Carter at a Senate Armed Services Committee in April.
"The 2001 authorization does not provide a legal justification for this war," he said. "I don't think we've sent a message of political resolve as the political leadership, as the decision makers contemplated in Article I of the Constitution. We've not sent a message of resolve to our troops ... we haven't sent that message to our adversaries."
A declaration of war would also meet the legal justification requirement he has called for. But it would go much further than what Kaine has called for.
If Kaine is picked as Clinton's running mate, it will be interesting to see if he and Trump stay on the same page on this issue.
But even if they do, the fallout Clinton continues to face over criticism from Trump and former primary opponent Vermont Sen. Bernie Sanders for her 2002 vote to authorize the Iraq War may mean some members of Congress will be in no rush to go on the record with a new vote. Some have suggested that their hesitation is part of why Obama's request for new authorization for action against ISIS hasn't yet passed Congress.
Could there be a court challenge to the ISIS campaign?
Yes, and there is. U.S. Army Capt. Nathan Michael Smith sued the Obama administration in May over what he said was the lack of proper congressional approval for the war against ISIS. Smith, an intelligence officer stationed in Kuwait, said he backed the campaign but added that he was seeking "to honor my oath" to the Constitution.
Earlier this month the administration's lawyers sought to dismiss the suit, arguing that because Congress had voted to provide funds to the anti-ISIS fight, lawmakers have, in effect, voiced their approval.
"The President has determined that he has the authority to take military action against (ISIS), and Congress has ratified that determination by appropriating billions of dollars in support of the military operation," the motion read. The court has yet to rule on the motion.
The lawsuit in theory could jeopardize Obama's ability to continue to fight ISIS without any further form of congressional approval. But the courts have largely deferred to Congress on issues such as these, and Congress is showing no signs of cutting off funding for the campaign.
Vladeck said the war powers act and legislative requirements that the commander in chief get authorization for using force are "more political than legal" restrictions. Obama has been able to wage the campaign against ISIS, and others such as Libya, without a specific congressional vote, but there can be political fallout for a president who takes military action without congressional approval.