Why Trump's iPhone tariff threat might not be enough to bring production to the U.S.

FILE PHOTO: Apple CEO Tim Cook escorts U.S. President Donald Trump as he tours Apple's Mac Pro manufacturing plant with in Austin, Texas, U.S., November 20, 2019.The once-solid relationship between President Donald Trump and Apple CEO Tim Cook is breaking down over the idea of a U.S.-made iPhone.Last week, Trump said he "had a little problem with Tim Cook," and on Friday, he threatened to slap a 25% tariff on iPhones in a social media post.Trump is upset with Apple's plan to source the majority of iPhones s ...