AMSTERDAM --- Dutch lawmakers will vote on Tuesday on a first step towards requiring King Willem-Alexander and his family to pay income tax, a plan that would require an amendment to the constitution. "A blue envelope for blue blood," Sandra Beckerman, a lawmaker from the left-wing Socialistische Partij, said during a debate on the issue on Thursday evening, referring to the blue envelope in which tax letters arrive in Dutch mailboxes. READ:Dutch king apologizes for country's role in slavery on 150th anniversary of abolition The initial motion, expected to be put to the vote on Tuesday, requires a simple majority to pass. It asks the government to propose a c...Keep on reading: Dutch parliament considers first step towards asking king to pay income tax