Europe frets as the Kremlin pushes the limits of its hybrid warfare

The Kremlin is testing Europe‘s limits. After months of covert attacks and sabotage across the continent, leaders are warning that Moscow may be about to grow bolder as it seeks to sow chaos and intimidate allies of Ukraine. Russian President Vladimir Putin could try to test NATO’s resolve to defend members on its eastern flank or respond to attacks that fall short of all-out war, these officials say, at a time when the U.S. is distracted by other conflicts and weighing reducing its military presence in Europe.