Story highlights A new poll has Kelly Ayotte trailing badly behind her Democratic challenger, Maggie Hassan

Ayotte has struggled with Donald Trump at the top of the Republican ticket

Washington (CNN) A key GOP interest group is set to run a new television ad calling on New Hampshire voters to re-elect their Republican senator as a check and balance for the White House.

The ad from the US Chamber of Commerce does not explicitly say the group believes Hillary Clinton will be president, but the intent is to make clear to voters that possibility is very real.

"America's future is far from certain," the narrator says over a picture of an empty presidential debate stage, followed by one of the White House.

"But no matter who the president is, New Hampshire needs a strong voice in the US Senate," the ad continues, declaring that incumbent Sen. Kelly Ayotte works across the aisle to get things done.

The ad reflects a growing sense among the establishment wing of the party that the White House is increasingly out of reach for its nominee, Donald Trump. Many Republicans are now shifting their focus to Capitol Hill, where the GOP's control of the Senate is on the line. Even the House, long seen as safely in Republican hands, could also be in play.

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