US Steel has urged a Canadian judge to throw out a government lawsuit that claims the steelmaker failed to live up to commitments it made when it acquired Stelco Inc. in 2007 and strike a section of the Investment Canada Act that allows the government to fine or force foreign companies to sell their Canadian operations. Lawyers for US Steel Corp. are arguing that Canadian foreign investment rules are unconstitutional because they deny companies the right to properly defend in court and should be declared void. The Canadian government sued US Steel last year, in the first such action since the Investment Act became law in 1984, claiming the Pittsburgh-based steelmaker failed to maintain employment levels and steel production at plants in Hamilton, Ontario. The government is seeking as much as CAD 14 million in fines, or an order forcing US Steel to sell the Canadian operations.