Donald Trump has extended his support in the 2016 presidential race among Republican primary voters to a record 40 percent as the field has narrowed, but he is still locked in a tight battle with Texas Sen. Ted Cruz for dominance, a new NBC News/Wall Street Journal poll shows. Trump gets the support of 40 percent of Republican primary voters, while Texas Sen. Ted Cruz gets 35 percent. Ohio Gov. John Kasich, in third place, has the support of 24 percent of GOP primary voters. The margin of error for Republican primary voters in the poll is +/- 5.6 percent....