The Marine Corps pushes into 2018 under a cloud of uncertainty.

The Corps’ leadership wants to grow the force, but how to pay for it remains unclear. Marines are still in Afghanistan training, advising and assisting in a classic counterinsurgency fight, but the Corps also feels a growing urgency to prepare for a full-scale conventional fight against a near-peer adversary like Russia or China. The readiness problems of the past five years are more pressing than ever — especially in Marine Corps aviation — but the top brass has been unable to offer a long-term solution.

Here’s a preview of what’s in store — and what’s in flux — for the Marines in 2018.

Tara Copp, Natalie Gross, Karen Jowers, Jeff Schogol, Leo Shane III, Shawn Snow and Todd South contributed to this report.