NBCnews.com — With more than 100,000 Russian troops deployed on Ukraine’s border, President Vladimir Putin is keeping the West guessing: Will he opt for a full-scale invasion or a more limited operation or simply keep Russian forces in place to maintain pressure on Kyiv and the West? Enjoying an overwhelming military advantage over Ukraine’s smaller, less advanced forces, Russia has a variety of options if Putin decides to launch an attack, depending on what Moscow wants to achieve, the price it is willing to pay and how the West responds, experts say. With Russia’s formidable air and ...