The White House finally admitted Friday what was abundantly clear to everyone: The United States is at war again.

But in the view of the administration, the "war" against the Islamic State of Iraq and Syria that President Obama described in his primetime address on Wednesday night is not a continuation of the conflict in Iraq, which he ended in 2011. It's actually the next front of the original Global War on Terror that President George W. Bush launched in the days after the terrorist attacks of September 11, 2001.

"The United States is at war with ISIL in the same way that we are at war with al Qaeda and its affiliates around the world," White House press secretary Josh Earnest said on Friday, referring to the acronym the administration uses to describe the Islamic State.

Both the declaration and the distinction are key for a couple of reasons.

For one, the White House effectively overruled the semantic dance that Secretary of State John Kerry engaged in on Thursday, when he refused to say the U.S. was at war – as opposed to merely a "very significant counterterrorism operation" – in an interview on CNN.

What we are doing is engaging in a very significant counterterrorism operation. It's going to go on for some period of time. If somebody wants to think about it as being a war with ISIL, they can do so, but the fact is it's a major counterterrorism operation that will have many different moving parts."

Earnest dispensed with the "counterterrorism operation" line Friday, repeatedly invoking the W-word during his daily press briefing. What he and the president want a war-weary public to understand is that this is a more surgical war than the full-scale invasion of Iraq. Obama has sworn up and down that he won't send U.S. ground combat troops to the Middle East again, and he has instead compared his strategy against ISIS to counterterrorism efforts in Somalia and Yemen, which the public largely ignored.

But the way Earnest described the conflict also has important legal significance. The White House is arguing that Obama does not need new authorization to use military force from Congress, which under the Constitution has the sole power to declare war. Instead, the administration is citing the original authorization for the use of military force that Congress gave Bush 13 years ago – just a week after 9/11 – to go after al-Qaeda.

A senior administration official cited that document in a background conference call with reporters ahead of Obama's speech on Wednesday.

We believe that he can rely on the 2001 AUMF as statutory authority for the military airstrike operations he is directing against ISIL, for instance.  And we believe that he has the authority to continue these operations beyond 60 days, consistent with the War Powers Resolution, because the operations are authorized by a statute."

In an indication of how quickly ISIS's advance snuck up on Obama, the administration had for months been asking Congress to "refine, and ultimately repeal" the 2001 authorization, only to reverse course and cite it as basis for its airstrike campaign in Iraq and potentially Syria.

But the administration's argument is somewhat dubious, because ISIS is now an entirely separate terrorist entity from al Qaeda, even though it is an offshoot of al- Qaeda's affiliate in Iraq. It also didn't exist in 2001.

The White House has argued that's an insignificant distinction, and Earnest's explanation on Friday had echoes of the way Bush described his own campaign against the terrorists: They declared war on us.

As Earnest put it on Friday:

This is not a situation where it’s the United States against ISIL. ISIL has indicated it is prepared to go to war against the rest of the world."