U.S.-Philippines ties are as strong as they’ve been in decades, with soldiers from both sides just wrapping up three weeks of joint military exercises that resemble the kind of preparations necessary to help repel a Chinese invasion of Taiwan.

Yet in the northern Philippines, near a military base the U.S. recently won access to that is crucial to any defense of Taiwan, Beijing has made inroads with key politicians. Manuel Mamba, governor of Cagayan province, has traveled to China twice in the past 12 months and has four copies of President Xi Jinping’s book "The Governance of China."

"We were VIPs, treated very, very well,” Mamba said of his visits to China. "We stayed in five-star hotels. We were free to roam around all over, even at night.”