Washington (AFP) – Are they invading or not? Russian President Vladimir Putin’s wily, inch-by-inch approach to Ukraine has made it hard for the United States and allies to craft their response to Europe’s biggest crisis since the Cold War. Since Moscow began massing tens of thousands of heavily armed troops on Ukraine’s borders weeks ago, US President Joe Biden has repeatedly warned of sanctions with “enormous consequences” if those troops invaded. But rather than a blitzkrieg-type offensive, Russia has edged its now 150,000-strong war force ever closer to the Ukraine frontier, announced it wo…