Adam Hamilton (D) defeated incumbent Roger Marshall (R) and David Graham (L) to win the general election for U.S. Senate in Kansas on November 3, 2026. Click here for detailed results.

This U.S. Senate race was among several that helped determine which party controlled the chamber. Heading into the election, Republicans had a 53-45 majority. AP's John Hanna wrote, "Republican-leaning Kansas has a sizable bloc of moderate voters ... and regularly elects Democratic governors. But Democrats haven’t come within 10 points of winning a Senate race in more than 50 years, and they haven’t won one since 1932."

According to The Cook Political Report, which rated the election a Toss-up, three factors made the race competitive in 2026: "[A] stronger-than-expected Democratic challenger who has a moderate message and credentials; an incumbent who was slow to wake up to the real threat both his opponent and the environment pose; and erosion in Trump’s support on the ground rooted in the agriculture economy’s struggles over high fuel and fertilizer prices and distrust over beef imports."

A similar competitive landscape existed in 2020, when Marshall was first elected by a margin of 11 percentage points. According to Politico's Kathy Gilsinan, "Then, too, the race featured tightening polls, a moderate, seemingly Kansas-friendly Democratic candidate, and millions rushing into the state in a year expected to be tough for Republicans."

Hamilton founded the largest United Methodist church in the country. He said, "People are struggling to pay for gas, groceries, housing, and especially health care. I'll work to bring those costs down: end the self destructive policies coming out of Washington like tariffs and war, crack down on the price-gouging and anti-competitive behavior that push up your bills to pad profits, get more homes built that working families can afford, and push for trade and tax policies that help Kansas families, farmers, and small businesses instead of making fertilizer, diesel, groceries, and everyday necessities more expensive." Former Kansas governors Bill Graves (R) and Mike Hayden (R) endorsed Hamilton.

At the time of the election, Marshall had served in the U.S. Senate since 2021. He previously represented Kansas' 1st Congressional District from 2017 to 2021. Before being elected to Congress, Marshall worked as an obstetrician-gynecologist and served in the U.S. Army Reserve. He said, "Here’s what I’ve fought for: permanent bonus depreciation so farmers can afford their equipment, higher estate tax exemptions so family operations can pass to the next generation, stronger crop insurance, and clean fuel tax credits that expand markets for Kansas corn and soy. Kansas farmers feed this country. They deserve a Senator who shows up, listens, and fights for them every single day." President Donald Trump (R) endorsed Marshall.

The outcome of this race affected the partisan balance of the U.S. Senate in the 120th Congress. Thirty-three of the 100 U.S. Senate seats were up for election, and another two seats were up for special election. Democrats held 13 of the seats up for election, and Republicans held 22.

At the time of the election, Republicans had a 53-45 majority in the chamber. To read more about the U.S. Senate elections that took place in 2026, click here.