Vienna — American politicians are at it again: punching oil cartel Opec. The cartel has often been a bogeyman for US politicians since the first oil crisis in 1973. Now Opec is facing a renewed political assault in Washington, directly from US President Donald Trump’s Twitter account, and quietly, but potentially more dangerously, from US Congress. In books and social media postings going back 30 years, Trump has repeatedly attacked Opec, saying oil prices should be about $30 a barrel and arguing Opec was stealing money from American citizens. The president’s track record is important now because US lawmakers have resurrected the so-called "No Oil Producing and Exporting Cartels Act," or Nopec, which proposes making the cartel subject to the Sherman anti-trust law, used more than a century ago to break up the oil empire of John Rockefeller. The bill was re-introduced in late May and cleared its first legislative hurdle last week when the House Judiciary Committee quickly sent it to ...