President Donald Trump has a prime opportunity to help lower costs for Americans in his meeting with Chinese President Xi Jinping, the top GOP lawmaker overseeing U.S. diplomacy told Fox News Digital.House Foreign Affairs Committee Chairman Brian Mast, R-Fla., argued that China is one of the biggest culprits in Americans' current struggle with high cost of living — particularly at the gas pump. He blamed China's willingness to arm Iran in its ongoing conflict with the U.S., which has wreaked havoc on global trade by effectively closing the Strait of Hormuz."If President Trump can secure that C...