The relationship between the United States and Ukraine has reached a pivotal moment, three years after Russian forces invaded its borders with the intent of overthrowing the government and annexing the territory.

Russia’s military was expected to quickly advance through the country until it overtook the capital when it invaded on Feb. 24, 2022, though it was met with a Ukrainian resistance that surprised the world. Since then, Ukraine’s military has effectively forced a stalemate in which Russia occupies about a fifth of Ukrainian territory in the eastern and southern parts of the country, but the front lines have largely stagnated.