Has a high-water mark for the scary U.S. investment deficit been reached?

One of the scariest numbers in world finance got even more frightening at the end of last year as America's skyrocketing investment deficit hit new highs. Whether it's now peaked is perhaps the most important question facing global markets today. The main thrust of President Donald Trump's global economic policies is clearly directed toward the U.S.'s yawning trade deficit, as he seeks to stop "freeloading" foreign countries from undercutting U.S. producers by overvaluing the dollar, frustrating U.S. exports and relying on American consumers. Valid or not, next week's sweeping U.S. import tariff hikes are aimed at correcting that. Less talked…