The job of a state legislator is to pass laws, but in Colorado, some are more effective than others. 

To figure out the most and least successful lawmakers of the state’s 2023 legislative session, Colorado Politics looked at the bills they prime-sponsored in both chambers and ranked the number of bills passed, percentage of bills passed and percentage of bills with bipartisan sponsorship, according to the Colorado General Assembly’s website. 

Democrats predictably won big this session after the November election increased their hold over the state legislature to a 69-31 split – the largest Democratic advantage in 85 years. But while Democrats topped the lists for most bills passed, Republicans led in bipartisanship, a reflection of their need to compromise with the supermajority to advance their legislative agenda. Plus, some categories that were one-party topics last year featured both this year, and vice versa. 

On average, each of the 100 lawmakers sponsored nearly 20 bills this year. The House and Senate approved approximately 82% of each legislator’s bills, and around 52% received bipartisan sponsorship.

Here’s how the top and bottom legislators stack up.

Most bills passed by number

Unsurprisingly, the top three lawmakers on this list are members of the Joint Budget Committee, whose responsibilities include the annual budget package, supplemental funding and about two dozen orbital bills to balance the budget. But unlike last year, JBC members didn’t dominate the entire top five. This year, Sens. Faith Winter and Dylan Roberts beat out three JBC members who ranked sixth, eighth and 10th in overall bills passed. 

First: Sen. Rachel Zenzinger, D-Arvada – 83 bills

Second: Rep. Shannon Bird, D-Westminster – 79 bills

Third: Sen. Barbara Kirkmeyer, R-Brighton – 49 bills

Fourth: Sen. Faith Winter, D-Westminster – 45 bills 

Fifth: Sen. Dylan Roberts, D-Avon – 44 bills 

Least bills passed by number

This list includes the House lawmakers that lean the furthest right ideologically, dubbed the far-right four: Reps. Stephanie Luck, Scott Bottoms, Ken DeGraaf and Brandi Bradley. The group often clashed with the Democratic supermajority, debating bills for hours, but not pursuing much legislation themselves. Bottoms, DeGraaf and Bradley – and the two Democrats on this list – are all first-year lawmakers. This is Luck’s second year in a row topping this list. 

First (tie): Rep. Stephanie Luck, R-Penrose; Rep. Scott Bottoms, R-Colorado Springs; and Rep. Ken DeGraaf, R-Colorado Springs – 1 bill 

Fourth: Sen. Jim Smallwood, R-Parker – 4 bills 

Fifth (tie): Rep. Tisha Mauro, D-Pueblo; Rep. Bob Marshall, D-Highlands Ranch; and Rep. Brandi Bradley, R-Littleton – 5 bills

Most bills passed by percentage

Sen. Rachel Zenzinger, chair of the Joint Budget Committee, also tops this list, passing every one of the 83 bills she introduced this session. Only Democrats achieved this perfect score, including party leaders like House Speaker Julie McCluskie, Senate President Steve Fenberg and House Majority Leader Monica Duran. First-year Reps. Kyle Brown, William Lindstedt and Ruby Dickson also managed to pass all of their bills. 

First: Sen. Rachel Zenzinger, D-Arvada – 100% of 83 introduced bills 

Second: Sen. Dylan Roberts, D-Avon – 100% of 44 bills

Third: Sen. Tony Exum, D-Colorado Springs – 100% of 18 bills 

Fourth: Rep. Meg Froelich, D-Englewood – 100% of 16 bills 

Fifth (tie): House Speaker Julie McCluskie, D-Dillon, and Rep. Lindsey Daugherty, D-Arvada – 100% of 15 bills

Honorable mentions: Senate President Steve Fenberg, D-Boulder (100% of 13); Rep. Monica Duran, D-Wheat Ridge (100% of 12); Rep. Kyle Brown, D-Louisville (100% of 11); Rep. William Lindstedt, D-Broomfield (100% of 11); Rep. Ruby Dickson, D-Greenwood Village (100% of 7); and Rep. Leslie Herod, D-Denver (100% of 7) 

Least bills passed by percentage

The far-right four similarly dominated this category. But they are unexpectedly joined by Democrat Rep. Serena Gonzales-Gutierrez, a leader of the House’s progressive caucus. Gonzales-Gutierrez ran for the Denver City Council during the session, winning her race in April. In her last legislative session, Gonzales-Gutierrez had the lowest bill success rate by percentage of any Democrat. Last year, no Democrats were featured on this list. 

First (tie): Rep. Scott Bottoms, R-Colorado Springs, and Rep. Ken DeGraaf, R-Colorado Springs – 20% of 5 introduced bills

Third: Rep. Stephanie Luck, R-Penrose – 33.3% of 3 bills 

Fourth: Rep. Brandi Bradley, R-Littleton – 50% of 10 bills

Fifth: Rep. Serena Gonzales-Gutierrez, D-Denver – 50% of 12 bills 

Most bipartisan sponsorship by percentage

As usual, the minority party swept this category. Holding only 31 seats of Colorado’s 100-member legislature, it is difficult for Republicans to pass bills without working across the aisle. The Democrat with the most bipartisan sponsorship, Sen. Jeff Bridges, only ranked 20th overall, with 81.6% of his bills having bipartisan sponsorship. Rep. Marc Catlin and Sen. Cleave Simpson have a history of bipartisan legislative success, making this top five last year, as well. 

First: Rep. Marc Catlin, R-Montrose – 100% of 17 introduced bills 

Second: Sen. Jim Smallwood, R-Parker – 100% of 5 bills 

Third (tie): Sen. Cleave Simpson, R-Alamosa, and Sen. Perry Will, R-New Castle – 96.3% of 27 bills 

Fifth: Sen. Kevin Van Winkle, R-Highlands Ranch – 94.7% of 19 bills 

Least bipartisan sponsorship by percentage 

Democrats exclusively comprise this list. With a supermajority in the House and a near-supermajority in the Senate, Democrats don’t need bipartisan support to pass their bills. However, this list has frequently featured both Republicans and Democrats in the past, including last year. Notably, four of these five lawmakers are House representatives, where Democrats have a stronger majority. Reps. Regina English, Ruby Dickson and Jennifer Parenti are all first-years. 

First: Rep. Regina English, D-Colorado Springs – 0% of 9 introduced bills

Second: Rep. Ruby Dickson, D-Greenwood Village – 0% of 7 bills 

Third: Rep. Tammy Story, D-Evergreen – 10% of 10 bills 

Fourth: Sen. Jessie Danielson, D-Wheat Ridge – 10.5% of 19 bills 

Fifth: Rep. Jennifer Parenti, D-Erie – 12.5% of 8 bills 

Most contrarian votes by number 

A new category this year: Colorado Politics looked at the lawmakers who voted against bills that every other lawmaker in their chamber voted in support of. This happened 57 times this session, with 18 lawmakers at one point being the sole “no” vote on a bill. All of the repeat offenders are included in this list, the bulk of whom are Republicans. Of the 10 unlisted lawmakers who cast contrarian votes only once, six are Republicans and four are Democrats. 

First: Sen. Mark Baisley, R-Woodland Park – 12 lone “no” votes 

Second: Sen. Kevin Van Winkle, R-Highlands Ranch – 11 votes

Third: Rep. Stephanie Luck, R-Penrose – 10 votes

Fourth: Sen. Paul Lundeen, R-Monument – 4 votes

Fifth (tie): Rep. Scott Bottoms, R-Colorado Springs, and Sen. Janice Rich, R-Grand Junction – 3 votes 

Honorable mentions: Sen. Kevin Priola, D-Henderson, and Sen. Julie Gonzales, D-Denver – 2 votes