Poll rundown: Close Senate races in battleground states

With top Republicans worried about the 2018 Senate races, every contested election matters and is worth following. New polling from two battleground races shows Democrats and Republicans are barreling toward a photo-finish for control of the U.S. Senate.

In Missouri and Montana, two Trump-supporting red states with incumbent Democrat senators, polling shows both races in a statistical tie.

Sen. Claire McCaskill, D-Mo., and her Republican challenger, state Attorney General Josh Hawley, are each polling 45 percent, according to a recent CBS News poll.

Meanwhile, Sen. Jon Tester, D-Mont., leads his GOP challenger, Matt Rosendale, 47-45 percent.

In Nevada, a recent Gravis poll shows incumbent Sen. Dean Heller, R-Nev., trailing his opponent, Democrat Jacky Rosen, by two points. Hillary Clinton won Nevada in 2016. It is a pivotal state where Democrats are looking to pick up a seat to flip the Senate.

One race that’s not close: In West Virginia, an Emerson College poll shows Sen. Joe Manchin, D-W.V., holding a double-digit lead over Republican state Attorney General Patrick Morrisey, 45-33 percent.

We have 50 days until the 2018 election. Republicans have work to do if they want to expand their Senate majority.