Apple (AAPL, Financials) finds itself in a familiar squeeze as tensions between the United States and China flare up again.

Nearly 90% of iPhones are still made in China, tying the company's fortunes to a country now facing renewed U.S. tariffs. Smartphones were spared for now, but former President Donald Trump has warned that more electronics could soon be targeted, keeping pressure on Apple's supply chain.

Apple's long relationship with China began in the 1990s and deepened when it partnered with Foxconn to build iPods and iPhones. Over the years, Apple helped create a powerhouse manufacturing ecosystem — one that now produces most of its devices. Today, 150 of its top 187 suppliers are based in China, according to Nikkei Asia.

Calls to move production to the U.S. are growing louder, but supply chain experts say replicating China's scale and speed would take years, if it's possible at all.

China is also pushing back, placing export controls on rare earth minerals critical to tech manufacturing. Inside China, Apple is losing ground to homegrown rivals like Huawei, Xiaomi, and Vivo, who have built on the very supply networks Apple helped establish. Last year, Apple slipped from its position as China's top smartphone seller.

Even a $500 billion investment in the U.S. might not fully protect the company from political or operational risks ahead. In China, Apple has already made concessions, limiting features like AirDrop and Bluetooth under government pressure.

The recent tariff exemption gives Apple a little breathing space. But with trade tensions escalating, that relief could be short-lived.