LIKE A KENNEDY in America, Kaja Kallas has carried both the privilege and the burden of her family name. Her father, Siim Kallas, an economist, was the first head of independent Estonia’s central bank, prime minister from 2002 to 2003 and the country’s European Commissioner from 2004 to 2014. (He is the only person to have been a member both of the European Commission and the Supreme Soviet, the Soviet Union’s legislature, in which he served briefly before the country’s collapse in 1991.) For years, even after becoming leader of the Reform Party her father had founded, Ms Kallas…