An internal poll conducted last week for one of the three Democrats hoping to deny U.S. Rep. Lauren Boebert another term in Congress shows potential challenger Ike McCorkle leading the Republican by double digits in Colorado’s 4th Congressional District. However, a whopping one-third of the voters surveyed said they were undecided.

McCorkle, a Marine veteran making his third run for the seat, led Boebert 41% to 27%, with 33% undecided in a hypothetical general election contest, a survey of likely general election voters released Tuesday by McCorkle’s campaign found.

The same poll showed former President Donald Trump 10 points ahead of President Joe Biden in the district, which covers Douglas County, Loveland and the Eastern Plains and is the state’s most reliably Republican congressional seat.

According to results reviewed by Colorado Politics, Trump had 45% to Biden’s 35%, with independent candidate Robert F. Kennedy Jr. polling at 6% and 14% of votes undecided. Trump won the district’s electorate by an 18.5 percentage point margin in 2020.

Boebert, a two-term lawmaker representing the Western Slope-based 3rd Congressional District, moved into the 4th CD at the beginning of the year. She is facing five other Republicans in Colorado’s June 25 primary for a full term in the seat vacated by Republican Ken Buck when he resigned from Congress in March.

A concurrent special election between Republican Greg Lopez and Democrat Trisha Calvarese will decide who will fill the remainder of Buck’s term through the end of the year.

Conducted by Gravis Marketing for McCorkle, the nonpartisan polling firm said the May poll surveyed 423 likely voters using online and text-based responses between May 22 and May 24. The poll’s margin of error was 4.7 percentage points.

The pollster said the survey’s sample included 45% unaffiliated voters, 36% Republicans and 19% Democrats. Hispanic voters accounted for 9% of respondents. Asked to describe their ideology, 41% of the poll’s respondents said they were conservative, 38% called themselves moderates, and 22% said they were liberal.

An earlier poll conducted for McCorkle by the same firm two months later found McCorkle leading Boebert by 7 points, with slightly fewer undecided voters. The March poll showed that Trump led Biden by 13 percentage points, with about the same level of undecided responses.

McCorkle told Colorado Politics that the polling shows Boebert is vulnerable despite the district’s strong Republican lean.

“All across District 4, we hear the same message from voters across party lines: extremism in Washington is the No. 1 threat to our democracy, and our campaign is the one to fight it and win,” McCorkle said in a text message.

“Our team’s hard work across this district has already doubled our lead over Lauren Boebert, while other Democrats in this race are still 10 points behind her. The math is clear; we are the only Democratic campaign that will be successful in November.”

A spokesman for Boebert’s campaign declined to comment on the Democrat’s new internal poll.

McCorkle is running in the primary against first-time candidate Calvarese, a former speechwriter for the AFL-CIO and staffer at the National Science Foundation, and John Padora, an engineer and addiction-recovery advocate.

Boebert’s primary opponents are former state Sen. Jerry Sonnenberg, R-Sterling, and state Reps. Mike Lynch, R-Wellington, Richard Holtorf, R-Akron, former talk radio host and nonprofit founder Deborah Flora and business consultant Peter Yu.

According to the most recent campaign finance reports, Boebert and McCorkle were the fundraising leaders in their primary fields. Through March 31, Boebert reported raising more than $3.4 million and had nearly $1 million cash on hand, while McCorkle raised close to $1 million and had more than $150,000 in the bank.

Ballots start going out to voters on June 3 and are due back to county clerks by 7 p.m. on June 25.