NATO’s 29th member is likely to be Montenegro. The alliance is keen to show that Kremlin harrumphing has not changed its open-door policy. And Montenegro (which separated from Serbia in 2006) has tried hard to shed its reputation as a playground for dodgy Russians. It signed up promptly for European Union sanctions after Russia’s attack on Ukraine, and when the alliance’s secretary-general, Jens Stoltenberg, and a delegation of ambassadors arrive today they will compliment the government on purging pro-Russian elements in the security services. Support for NATO membership is growing, though it is still under half the population (and a protest demonstration will greet the visitors). NATO bombed targets in Montenegro in 1999 in the Kosovo war and ties with Serbia—still far from the alliance—are strong. Progress on entrenching democracy and battling corruption has been fitful. But geopolitics should trump such shortcomings and bring a membership invitation in December.