The United States is taking new steps—steps it once said it would not take—to help Ukraine in the fight against Russia. Ukraine gets the Patriot anti-missile system and Ukrainian soldiers get a free trip to Oklahoma to train in how to use it. This is a necessary and inevitable step, but before we take the next one it's important to take into account how we got here—and how far we are willing to go. The West has hesitated at every step along the way to war, and for good reason. When Crimea was lost to Russia in 2014, the U.S….