• President Joe Biden says the 20-year U.S. military mission in Afghanistan will end by August 31.
• “This was a huge win today, for all of our Afghan friends and allies,” said Rep. Seth Moulton, a Marine who served four tours in Iraq. “For the last several weeks, I have been asking for three things, in particular, from the [Biden] administration: a detailed plan, a commander to be in charge of it, and a commitment to see the mission through, and today the president mentioned all three of those.”

Rep. Seth Moulton, D-Mass., has long advocated for a plan to evacuate the nearly 18,000 Afghan interpreters, allies and their families from Afghanistan before the full withdrawal of U.S. troops. He told CNBC's "The News with Shepard Smith" that President Joe Biden's speech Thursday represented a step in the right direction. 

"This was a huge win today, for all of our Afghan friends and allies," said Moulton, a Marine who served four tours in Iraq. "For the last several weeks, I have been asking for three things, in particular, from the [Biden] administration: a detailed plan, a commander to be in charge of it, and a commitment to see the mission through, and today the president mentioned all three of those."

Moulton noted that the president did not specifically name a commander, and that he'd like to see the specifics of how the U.S. will "get Afghan interpreters from far-flung, rural parts of the country to a central evacuation point."

Biden announced the U.S. military will complete its withdrawal from Afghanistan by August 31, nearly two weeks earlier than his deadline of September 11. He reaffirmed in his speech that the U.S. will "continue to make sure that we take on the Afghan nationals who work side-by-side with U.S. forces," and that the U.S. has "already dramatically accelerated the procedure time for Special Immigrant Visas to bring them to the United States."  

Host Shepard Smith also asked Moulton about whether or not he thinks the Taliban will take over Afghanistan once the U.S. withdraws completely from the country. Moulton said that the U.S. should be prepared, no matter the outcome. 

"Look, the bottom line is, we've got to be prepared for either eventuality, and one of the questions I'm going to be asking in detail, especially in classified sessions with the Armed Services Committee is, what contingency plans they have for the possibility that the Taliban does just simply overrun the Afghan government," Moulton said. 

Biden defended the U.S. military's rapid withdrawal from Afghanistan after a reporter asked if the Taliban takeover in the country is inevitable. 

"The Afghan troops have 300,000 well equipped, as well equipped as any army in the world, and an air force, against something like 75,000 Taliban," Biden said. "It is not inevitable."

Moulton said that while he doesn't know that he has as much faith as Biden does in the Afghan security forces, he does think the president is correct in saying "we have provided them a lot of capacity."

America's longest war has cost the lives of around 2,300 U.S. troops and left thousands more wounded. More than 100,000 Afghans are estimated to have been killed or wounded since the conflict began. The U.S. has spent $825 billion on combat operations, according to the Department of Defense via a CRS report for Congress. 

The White House did not immediately respond to CNBC's request for comment.