President Biden said the United States is “rallying the world to stand with Ukraine” and pledged to support the cause “as long as it takes.” U.S. officials have downplayed the (Russian} gains, calling them halting and incremental. The scrutiny is fueled by U.S. government assessments of other wars, notably in Afghanistan, where officials habitually glossed over widespread dysfunction and corruption and sidestepped questions of whether battlefield successes were not only achievable but sustainable. A Ukrainian lawmaker shared similar concerns. “We are losing the most valuable thing, our soldiers and officers.” Benjamin Friedman, a policy director at Defense Priorities, said that...