obamalordstown1 GM's Lordstown, Ohio assembly plant has become a symbol of both GM's hard times and its best hopes for a turnaround after a $50 billion federal investment. A recent bump in sales because of the government's "Cash for Clunkers" program has allowed GM to call back more than 1,000 workers from layoff.   So it was a natural backdrop for a return visit by President Obama, who held a roundtable with workers and then gave a stump speech from the factory floor for his economic policies and health care reform.   But this is not your father's GM anymore and nothing about it as clear-cut as it seems -- even if you are the leader of the free world and head of the government that holds a controlling stake in the automaker.     At one point, Obama -- veering from his prepared remarks -- suggested that health-care reform would allow the UAW-represented workers in the audience to negotiate better wages.