As the Trump administration moves to take on China over intellectual property, Washington will find it has limited firepower. Beijing has a strong grip on American technology companies, and global trade rules could favor China. Technology is proving a major battleground for China and the United States, as both sides vie to protect their economic and national security interests. Beijing has forced a long list of American companies to enter joint ventures or share research with Chinese players, part of a broader push to create its own technology giants. From makers of smartphones to chips to electric cars, American businesses have reluctantly agreed, fearful of losing access to China, which has the second-largest economy in the world.