Rules that place new restrictions on American investment in China opened for public comment this week. The new proposed regime comes after years of concern about China's technological advancement, originating with U.S. investment, and the country's use of that technology against American interests. And while the effort has rare bi-partisan support, lawyers in the international investment and national security space expect it to make life much harder for U.S. investors looking to spend money overseas. 

"It's another step to address growing concern in the U.S. about potentially leaking critical technologies as well as investment into countries like China," said Mick Tuesley, head of  Simpson Thacher & Bartlett's National Security Regulatory Practice.