Europe's leaders have woken up to hard power

Not enough is said about the other Donald T. Having led Poland between 2007 and 2014, Donald Tusk can take some credit as his nation approaches western European standards of living. Now in his second stint, Ukraine has no more vociferous friend in the world. Talk of Poland as the eventual heir to Britain - a pro-market, pro-American and martial voice in the EU - seems rash. It has around half the population and less diplomatic clout. But Tusk's ease in those institutions as a former Brussels grandee narrows the gap. Whatever Europe lacks as it tries to become a…