Open this photo in gallery: Polish President Andrzej Duda in Warsaw, Poland, on April 19.Michal Dyjuk/The Associated Press Hundreds of thousands of people marched in an anti-government protest in Poland’s capital on Sunday, with citizens travelling from across the country to voice their anger at officials who they say have eroded democratic norms and created fears that the nation is following Hungary and Turkey down the path to autocracy. Warsaw Mayor Rafal Trzaskowski, who belongs to the opposition party that led the march, estimated that 500,000 people took part. The Onet news portal estimated there were at least 300,000 at...