Republicans are confronting an increasingly concerning political situation in Kansas, where a Senate seat the party has held for more than a century has become unexpectedly competitive.

Sen. Roger Marshall (R-KS) is facing Democrat Adam Hamilton in a reelection contest that recent polling suggests is within single digits, despite the Sunflower State not having elected a Democrat to the U.S. Senate since 1932.

During an appearance on Fox Business Network's Big Money, Marshall was pressed about why the race remains so close.

"Well, no, I think it's the price of gasoline," Marshall declared. "It's that simple, and I'm not sure it's as close as what the national polls are showing. Six years ago, I was an open seat. The poll showed the same thing, and we won by 11 points. Now, I don't think we're going to win by 11 points right now."

Marshall also blamed negative media coverage of President Donald Trump for shaping perceptions of the economy.

"The national media, the legacy media has just beat the heck out of President Trump now for, what, 10 years, and despite what's really a pretty strong economy here in Kansas, the legacy media is just telling you the sky is falling," the senator said.

The national polling shows why the senator's worried.

An ABC News/Washington Post/Ipsos survey found that 71% of Americans consider gasoline unaffordable, compared with 28% in February. Additionally, a Pew Research Center survey found that 74% of Americans are very concerned about gasoline and energy prices, up from 43% in January.