Meryl Streep's two films with Phyllida Lloyd, Mamma Mia and this silly biopic, demonstrate that even when the world's greatest actress is at the peak of her powers — whether dramatic, comic, or musical — it's not enough. Here she uncannily impersonates Margaret Thatcher, the most powerful British Prime Minister since Churchill, not just in her crypto-fascist, harridan glory days, but in her twilight years as she suffers from dementia. It's in the latter period that Lloyd starts out, sending Maggie back in flashbacks to milestones in her life, such as her first run for MP, her election as PM, her draconian economic measures, her triumph in the Falklands, and an assassination attempt by the IRA. The jolly shade of her dead hubby Denis (Jim Broadbent) spurs her on, a ploy like the one in Ron Howard's A Beautiful Mind, if not Dickens's A Christmas Carol. Streep's performance notwithstanding, this Lady suffers from iron deficiency.