A new NBC/Wall Street Journal poll is out:

In the survey, 50 percent of likely voters say they prefer a Republican-controlled Congress, versus 43 percent who want Democrats in charge.
Last month, Republicans held a 46 percent to 43 percent advantage among likely voters on this question.
The GOP’s current seven-point lead, McInturff observes, is on pace — historically — to result in a shift of power in Congress. “The Democrats, with two weeks left, are facing very, very difficult arithmetic.”

More here.