Senate map 'historically difficult' for Dems, says pollster

Pollster Dan Cox in an interview that aired Tuesday on "What America's Thinking" said that the Senate midterm map for Democrats is "historically difficult" this year. 

"The map was never that favorable to Democrats to begin with," Cox, research director at the Public Religion Research Institute, told Hill.TV's Joe Concha. "It was a historically difficult map for them in places like Missouri, Arizona, North Dakota. They're trying to compete in places like Georgia and Texas, but those are kind of longshots."

"If you look at Texas, in particular, there has been so much tension on this race, but if you look at the polling, every statewide race, the Republican is leading," he continued. 

While Democrats appear to have a strong chance of taking back the majority in the House, Republicans appear poised to hold on to the Senate.

Democrats need 23 seats to regain control in the Lower Chamber and gives them a nearly 86 percent chance of taking the House. But the Senate map provides a difficult challenge.

Democrats are defending Senate seats in ten states that President TrumpDonald John TrumpO'Rourke: Trump driving global, U.S. economy into recession Manchin: Trump has 'golden opportunity' on gun reforms Objections to Trump's new immigration rule wildly exaggerated MORE won in 2016 and already needed to pick up two more seats to gain the majority in the Upper Chamber. gives the Democrats only a 16 percent chance to win the Senate.

Some closer Senate races have shifted to the right in recent weeks.

A Quinnipiac University poll released on Monday showed Sen. Ted CruzRafael (Ted) Edward CruzTrump moves forward with F-16 sale to Taiwan opposed by China The Hill's Campaign Report: Battle for Senate begins to take shape O'Rourke says he will not 'in any scenario' run for Senate MORE (R-Texas) leading his opponent Rep. Beto O'RourkeBeto O'RourkeO'Rourke: Trump driving global, U.S. economy into recession 2020 Democrats feel more emboldened to label Trump a racist Hillicon Valley: O'Rourke proposal targets tech's legal shield | Dem wants public review of FCC agreement with T-Mobile, Sprint | Voters zero in on cybersecurity | Instagram to let users flag misinformation MORE by five points in their race, while Republican Josh Hawley has a slim lead over Sen. Claire McCaskillClaire Conner McCaskillEx-CIA chief worries campaigns falling short on cybersecurity Ocasio-Cortez blasts NYT editor for suggesting Tlaib, Omar aren't representative of Midwest Trump nominees meet fiercest opposition from Warren, Sanders, Gillibrand MORE (D-Mo.) by an average of two points in Missouri's Senate race, according to Real Clear Politics.

RealClearPolitics average of polls also gives challenger Mike Braun (R) a slim edge in Indiana against Sen. Joe DonnellyJoseph (Joe) Simon DonnellyLobbying world Trump nominees meet fiercest opposition from Warren, Sanders, Gillibrand GOP frets over nightmare scenario for Senate primaries MORE (D).

— Julia Manchester