Colorado State Senate: Which Party Wins Control in 2026

Colorado's U.S. Senate contest pits Democratic incumbent John Hickenlooper, seeking a second term after a career as Denver mayor and governor, against Republican state Sen. Mark Baisley of Woodland Park. Baisley campaigns on fiscal restraint, government accountability, property tax reform and expanding first-time homebuyer access, drawing on his aerospace engineering background and work on tech and defense issues in the legislature. Hickenlooper points to his record capping insulin costs, expanding Medicare drug price negotiation, and opposing Trump administration policies on public lands, tariffs, and healthcare cuts, while emphasizing water and healthcare expertise from his time as governor.

Colorado has trended Democratic in recent federal elections, though Republicans have won statewide Senate races before — Cory Gardner held the seat until Hickenlooper unseated him in 2020. With Democrats and Republicans nearly even in active voter registration and unaffiliated voters forming the largest bloc, the race is being watched as a test of whether Republicans can flip a statewide seat amid broader national political headwinds.

Colorado, once a reliable Republican state, has leaned decidedly Democratic in recent cycles, and 2026 looks similar. Gov. Phil Weiser and Sen. John Hickenlooper are favored for easy wins over underfunded Republican opponents Victor Marx and Mark Baisley, with some GOP figures, including former Rep. Ken Buck, crossing over to back Weiser. The closest races are in the U.S. House: Democrat Manny Rutinel is seen as favored over Republican incumbent Gabe Evans in District 8, while Republican incumbent Jeff Crank is expected to hold District 5 against well-funded Democrat Jessica Killin despite backlash over the Space Command relocation. Analysts attribute the overall Democratic advantage to anti-Trump sentiment and weak Republican statewide recruitment.

Colorado Republicans head into the 2026 election cycle with a statewide slate widely criticized as among the weakest in party history, with gubernatorial candidate Victor Marx at the center of multiple controversies. Marx was fined $57,000 for exceeding legal campaign donation limits, has faced scrutiny over fabricated claims about rescuing trafficking victims, and was found to have used manipulated and AI-altered imagery in campaign materials. Video also surfaced of Marx describing past incidents of violence toward his wife and son.

Marx is not alone: election deniers Mark Baisley and James Wiley are running for U.S. Senate and secretary of state respectively, wealthy independent Bob Chew has self-funded a long-shot Senate bid, and perennial candidate Greg Lopez is making a third gubernatorial attempt, this time as an independent. Critics attribute the party's decline to campaign finance changes, the rise of direct digital fundraising bypassing party vetting, and increasing ideological polarization that has narrowed the primary electorate. The weakened GOP field raises questions about competitive balance in Colorado's statewide races against well-established Democratic contenders.

Colorado's U.S. Senate race has sharpened into a proxy fight over President Trump's military campaign against Iran, with Republican state Sen. Baisley and Democratic incumbent John Hickenlooper clashing in their only televised debate on 9News. Baisley defended the strikes as overdue given decades of Iranian-backed attacks on Americans, acknowledging rising gas prices but arguing the cost is worth standing up to "bullies." He stopped short of backing ground troops in Iran.

Hickenlooper called the war reckless, pushing instead for negotiations to curb Iran's nuclear ambitions while conceding past administrations, including Obama's and Biden's, hadn't pressed hard enough. He left room for limited strikes if Iran blocked inspectors but opposed regime change. He has made war opposition central to his campaign, backing a war-powers resolution and featuring the issue in his first general election ad. The two also split over Trump's easing of sanctions on Russian diesel, which Hickenlooper called a political betrayal. Hickenlooper remains the favored candidate heading into the midterms.

Colorado Democrats closed out a six-day, 25-stop statewide bus tour by framing the midterms as a referendum on Donald Trump, betting that voter frustration with his administration will boost turnout. Sen. John Hickenlooper blamed Trump's tariffs, the Iran conflict and health care cuts for a "cost of living catastrophe," while attorney general nominee Jena Griswold pledged to sue to protect voting rights and immigrant communities. Candidates also cited Trump's moves against Colorado, including relocating U.S. Space Command, denying disaster aid and vetoing a water project. Republicans, hampered by infighting, countered that Democrats themselves are to blame for high living costs. Democrats are defending statewide offices and congressional seats while eyeing veto-proof legislative majorities.

Arizona Democratic Reps. Greg Stanton, Yassamin Ansari and Adelita Grijalva reported suspicious letters, some containing unknown substances, sent to former office addresses, following a similar incident at Secretary of State Adrian Fontes' office that prompted an Arizona Capitol evacuation; the substance there proved non-hazardous. The FBI, U.S. Postal Inspection Service and U.S. Capitol Police confirmed a broader nationwide pattern, with over 800 suspicious envelopes sent to congressional and election offices. Colorado lawmakers including Sen. John Hickenlooper and Reps. Joe Neguse, Jason Crow, Brittany Pettersen and Diana DeGette also reported receiving or intercepting such letters. Staff were unharmed; officials called the mailings an intimidation attempt and vowed continued investigation.

Colorado's congressional delegation is voicing growing concern over artificial intelligence, though members diverge on how—or whether—Washington should respond. Rep. Brittany Pettersen called for stronger industry standards, including independent audits and mandatory incident reporting. Sen. John Hickenlooper, who co-introduced bipartisan legislation on AI testing standards, warned the country is "entering a new and dangerous era" and urged the White House to address the technology's risks. Rep. Jason Crow echoed concerns about privacy and national security.

Sen. Michael Bennet argued Congress "will never be able to move fast enough" to regulate AI directly and instead proposed creating an independent federal agency for oversight. Republicans showed a different emphasis: Rep. Gabe Evans backed "common sense guardrails" and helped pass a House bill targeting AI data center costs, while also promoting American-made AI models over foreign competitors. Rep. Jeff Crank called for safety nets from AI companies themselves. The mixed responses highlight an unresolved national debate over federal AI oversight, with implications for markets tracking regulatory timelines and outcomes.

New Hampshire held primary elections Tuesday to pick nominees for Congress, governor and the state Legislature, with Sen. Jeanne Shaheen's retirement reshaping the ballot. Rep. Chris Pappas led a five-way Democratic Senate field that included progressive challenger Karishma Manzur, a research scientist and democratic socialist whose late surge, fueled by criticism of Pappas' pro-Israel donor support and his "present" vote on restricting arms sales to Israel, narrowed his once-commanding lead despite his large fundraising advantage and Shaheen's endorsement. On the Republican side, John Sununu, endorsed by President Trump over rival Scott Brown, held a wide edge among eight candidates; both Sununu and Brown are former senators previously defeated by Shaheen. The seat is one of a handful nationally that could help decide Senate control, with Democrats needing a net gain of four seats.

Pappas' departure from the 1st District opened a crowded race, with Stefany Shaheen (Jeanne Shaheen's daughter) and Maura Sullivan leading a nine-person Democratic field; Republicans chose among five candidates including Trump-endorsed businessman Anthony DiLorenzo and repeat candidate Hollie Noveletsky. In the 2nd District, Democratic Rep. Maggie Goodlander faced a primary challenge from state legislator Paige Beauchemin, while Republicans chose from candidates including repeat nominee Lily Tang Williams. Gov. Kelly Ayotte easily advanced toward a second term against two Republican rivals, favored against unopposed Democrat Cinde Warmington. Winners have eight weeks to campaign before the November 3 general election, as New Hampshire shifts future primaries to June starting in 2026.

Colorado's November 2026 ballot includes seven proposed constitutional amendments and seven statutory propositions covering immigration enforcement, natural gas rights, hunting and fishing, election procedures, redistricting, taxation, criminal penalties, transgender policy, and transportation funding. Constitutional amendments require 55% approval; propositions need a simple majority.

Notable measures include Amendment 81, which would require police to report violent crime suspects who are in the country illegally to federal immigration authorities, reversing a 2019 state law; Amendment 87 and competing Proposition 136, which offer opposing visions for the state's flat versus graduated income tax; and Proposition NN, which would let the state keep and spend TABOR surplus revenue on K-12 education. Other measures address mail-ballot ID requirements (Amendment 84), plain-language ballot drafting (Amendment 85), congressional redistricting rules (Amendment 86), harsher penalties for fentanyl sales and child sex trafficking (Propositions 132 and 133), sports participation and gender-related medical restrictions for minors (Propositions 134 and 135), sporting-goods tax revenue for conservation (Proposition 137), and a Front Range passenger rail sales tax. Political commentators Tom Cronin and Bob Loevy offered mixed endorsements across the measures.

A second former aide to Colorado state Rep. Sheila Lieder, a Littleton Democrat, has filed suit alleging she forced him to perform campaign duties while on the clock as a taxpayer-funded legislative aide. Nick Buttrey's lawsuit, filed in Denver District Court, names Lieder and the state of Colorado and claims the conduct violated the Fair Campaign Practices Act, which bars use of state resources for political campaigns.

Buttrey says he served as Lieder's senior legislative aide starting in December 2024 and later became her campaign manager without adequate pay, despite an understanding the role would be compensated. He alleges Lieder repeatedly demanded campaign work during aide hours, retaliated after he objected and reported the issue, and fired him in June citing performance issues. Lieder, who is running for state Senate in the Nov. 3 election, has not commented. This marks the second lawsuit against her from a former aide in as many months, following similar allegations by another aide in August, and adds to a string of mistreatment claims against Colorado legislators over the past year.