Mitt Romney may be down on China and threatening to declare Beijing a currency manipulator from day one if he is elected president, but his past dealings with the country show he was not always so hostile.

From his early days at private equity firm Bain Capital to his time as Massachusetts governor, Romney welcomed investments from China, and bought and expanded companies that benefited from its low labor costs and controlled currency. As chairman of the 2002 Winter Olympics, he also said Beijing should not be punished for human rights abuses.

All this is in sharp contrast to the Republican presidential candidate's current line of attack on the world's second-largest economy, which is now the United States' most important trading partner and largest foreign creditor. And that makes political strategists, China experts and business leaders wonder whether Romney will really follow through on his campaign promises if he is elected.