Those results come from the latest NBC News/Wall Street Journal poll. The telephone survey of 400 Republican primary voters, conducted Jan. 9-13, carries an error margin of 4.9 percentage points.
In a survey of the entire field, Trump draws 33 percent, giving him a double-digit margins over Cruz (20 percent), Florida Sen. Marco Rubio (13 percent) and retired neurosurgeon Ben Carson (12 percent). New Jersey Gov. Chris Christie and former Florida Gov. Jeb Bush each draw 5 percent.
Yet when choices are narrowed to just the top two Republicans, Cruz leads Trump by 51 percent to 43 percent. Pitted against Rubio, Trump leads 52 percent to 45 percent.
In a three-way contest with the top three Republicans in the poll, Trump leads with 40 percent to 31 percent for Cruz and 26 percent for Rubio.