A long run of dominance from U.S. stocks could be ending.U.S. stocks have done very well for the past 15 years. According to research by Dodge & Cox, U.S. stocks outperformed international stocks by over 500% from 2010 through last year.Yes, the United States is an economic juggernaut and a pillar of the world's economy. That said, the U.S. stock market is near its highest valuation on record, leaving a significant valuation gap between U.S. and international stocks.But investing in non-U.S. companies isn't ...