BEIJING - As a dangerous confrontation flared between China and Taiwan in 1996, Bill Clinton deployed the Seventh Fleet to deter the two rivals from going to war. Five years later, when a U.S. spy plane collided with a Chinese fighter, George W. Bush faced a prolonged international crisis. Meanwhile, human rights and democracy in China were a perennial hot-button issue.

Now it’s Barack Obama’s turn to deal with the China challenge, and this time, it’s all about the money. As the global financial system teeters, China, with its $1.9 trillion in foreign reserves and slowing but still strong economy, offers a potential lifeline.