PENTAGON - On the cusp of 2017, the United States is still involved in wars against Islamic extremists in Afghanistan and Islamic State militants in Iraq and Syria.

The tactical fight against IS militants is slowly progressing, but it is unclear yet how involved the incoming administration of Donald Trump will be in resolving the Syrian crisis.

FILE - Syrian soldiers fire their weapons during a
Syrian soldiers fire their weapons during a battle with rebel fighters at the Ramouseh front line, east of Aleppo, Syria, Dec. 5, 2016.

"In Syria, we have really no strategy for ending the civil war," said defense expert Michael O'Hanlon of the Brookings Institution, a Washington policy research group. "Mr. Trump implicitly may be willing to let President [Bashar al-]Assad win the war, but I'm not sure that is really a viable way forward because Assad has so much blood on his hands."

Afghan security forces keep watch in front of a mo
Afghan security forces keep watch in front of a mosque where an explosion happened in Kabul, Afghanistan, Nov. 21, 2016.

The war for Afghanistan is in its 15th year. International troops have been drawn down from about 140,000 in 2011 to fewer than 15,000 troops today, and O'Hanlon said the new U.S. defense team might want to consider increasing international troop numbers in the short term.

"There's no reason we have to avoid doing a little more if that helps take some of the pressure off the Afghan military and police. [It] gives them a little more time to build themselves up to recover from the huge losses they've been taking," he said.

But while the U.S. has been fighting extremism around the globe, major powers Russia and China have been modernizing their military forces.

David Ochmanek, a defense analyst with the RAND Corporation, a global policy think tank in Santa Monica, California, said that "because we've been so focused on prosecuting operations against ISIS, stabilizing Afghanistan and Iraq, and because we've been living under the constraints of the Budget Control Act since 2012, we haven't been able to buy the modern equipment that it takes to counter these new capabilities that countries like Russia and China are fielding."

FILE - Donald Trump, at the time still President-e
U.S. President-elect Donald Trump arrives to speak during 'thank you" tour event at Giant Center in Hershey, Pennsylvania, Dec. 15, 2016.

Trump in his stump speeches has been promising a military buildup.

"We have the greatest people in the world in our military," he has said. "We are going to rebuild our depleted military, and we're going to finally take care of our great, great veterans."

Ochmanek said the U.S. needs to spend its money on things like cruise missiles and air-to-air missiles. Those are the things, he contended, that can give the military more leverage to deter threats.