The war in Ukraine has been defined by several key trends this past year: Russia has underachieved. Ukraine has overachieved. Western support for Ukraine has remained surprisingly strong.
But there's no guarantee the conflict will remain on the same trajectory as we enter the second year of Russia's full-scale invasion.
Military analyst Michael Kofman says the Russian and Ukrainian militaries have both changed markedly after a year of heavy fighting.
"Neither of these armies look today the way they did at the beginning of the war. Both have taken heavy losses. Both have lost a lot of their best people and best equipment," said Kofman, an expert on the Russian military at the Center for Naval Analyses.
When Russia attempted a rapid takeover a year ago, its military rumbled into Ukraine with huge stockpiles of hardware.
But analyst Dmitri Alperovitch says a key reason the Russians failed is that they didn't send enough troops to capture and hold large parts of Ukraine.
"So if at the beginning, they didn't have enough troops, but they had plenty of equipment, now it's sort of the reverse, where they're flowing more troops in, but they may no longer have enough equipment to actually execute a successful campaign," said Alperovitch, who heads a think tank, the Silverado Policy Accelerator.
Russia faces military equipment shortages for a couple of reasons.
First, it burned through massive amounts of ammunition at an unsustainable rate, according to many analysts. Second, Russia lost half its tanks in the past year, according to a recent U.S. Defense Department estimate.
Kofman doesn't think the Russian military has gotten better over the past year, and he doesn't expect the Russians to make any major advances.
However, because Russia retreated from a good deal of Ukrainian territory last fall, "the Russian military substantially reduced the amount of territory they have to defend," he said. "That means that as a military, they have far more force density. They have echelon lines. They have reserves."
So Russia may be relatively well positioned to defend its current strongholds in the eastern region of the Donbas and the southern peninsula of Crimea.
Ukraine looks to carry out a new offensive
This brings us to the second key trend: Ukraine's successful offensive in the fall and whether that can be repeated in the spring.
In the coming months, Ukraine will likely find it harder to locate and exploit Russian vulnerabilities, according to Alperovitch.
"I think it's going to be very difficult for the Ukrainians to make quick progress," he said. "Unless the Russian line just collapses, I think it's going to be difficult to see the type of lightning offensives that we saw last year."
If both sides have trouble carrying out large-scale offensives, this means the coming year could become a grinding stalemate.
"Neither side, frankly, has demonstrated a great proficiency at combined arms. Neither side has air superiority, which is really important if you're going to take these fortified positions," Alperovitch said.
Both sides are widely expected to launch offensives. In fact, a Russian one appears to be underway in the east, and Russian forces have already suffered one resounding defeat around the town of Vuhledar.
Western support for Ukraine has been strong — so far
If neither side makes big advances, this could take us to the third key trend: the durability of Western support for Ukraine.
U.S. and European aid has been much stronger than many anticipated. Just last month, Western countries pledged the biggest military assistance package yet, including, for the first time, tanks.
But this backing may not last forever, says Russia expert Julia Ioffe, who writes for Puck.
"I do think at some point, Western support will start fraying, especially as the political winds change in the U.S.," Ioffe said, pointing to a group of Republicans in the U.S. House who are questioning U.S. aid.
"You are seeing these reassertions of an isolationist kind of 'America First' sentiment of, 'Why are we in this fight? Why are we sending a blank check to Ukraine? We shouldn't be doing this,'" she added.
Alperovitch noted that stockpiles of Western weapons are not infinite.
"The main issue is not actually the will to support the Ukrainians on the Western side. It's the capacity to do so," he said. "The rate at which the Ukrainians are expending munitions exceeds the production capacity of even the collective West."
Heading into the next year of the war, Kofman urges everyone to show a little humility.
"You have to be humble, specifically in the area of predictions, because experts actually are usually bad at predictions," he said.
In an unpredictable war, he said, expect the unexpected.
Greg Myre (@gregmyre1) is an NPR national security correspondent who has reported from Ukraine during the past year of the war.
