Chess legend Judit Polgar on Monday turned down Hungarian Prime Minister Peter Magyar’s offer to join his push to break with the Viktor Orban era as the country’s president. The pro-European conservative had nominated Polgar, widely considered the greatest woman to have taken to the chequered board, as a figure from outside politics to help carry out his promise of “regime change” from Orban’s hardline 16-year tenure. “I do not feel I have the strength to take on the historic responsibility of...