2018

Casten announced his candidacy for the United States House of Representatives in Illinois's 6th congressional district in September 2017.^[3] He defeated six other contenders in the 2018 Democratic primary to become the party's nominee against six-term incumbent Republican Peter Roskam.^[14]

On November 6, 2018, Casten won the election, defeating Roskam by a margin of seven points.^[15]

This race was viewed as one that Democrats needed to win in order to regain control of the U.S. House of Representatives for the first time since the 2010 elections.^[16] Illinois's 6th congressional district supported Democratic presidential nominee Hillary Clinton by about 7 percentage points in the 2016 presidential election.^[17] This was one of 25 GOP-held seats in the U.S. Representatives that Clinton carried in 2016;^[18] Democrats flipped 22 of them in 2018.^[19][20]

2020

Casten was reelected in 2020, defeating former state legislator and gubernatorial primary candidate Jeanne Ives by seven points.^[21]

2022

For his first two terms, Casten represented a district covering parts of five counties in Chicago's western suburbs, including Wheaton, Palatine, and Barrington.

Redistricting after the 2020 census saw the 6th become significantly more compact. Casten lost all of his territory outside Cook and DuPage counties. To make up for the loss in population, the district was pushed further into Cook County, absorbing a slice of southwestern Chicago proper. As a result, it lost its connection to longtime Republican Congressman Henry Hyde, who held the seat from 1975 to 2007.

The reconfigured district included a large chunk of the old 3rd district, represented by fellow Democrat Marie Newman. Although the reconfigured district retained Casten's district number, it was geographically more Newman's district than Casten's. According to calculations by Daily Kos, the new district was over 77% new to him; Newman retained 41% of her constituents while Casten retained 23% of his former territory.^[22] Nevertheless, Casten won the nomination. In the general election, he defeated Orland Park Mayor Keith Pekau by 8 points.

Climate change and energy

Casten says his number one issue in Congress is energy policy and climate change.^[24][25][26] He is a member of the House Select Committee on the Climate Crisis.^[27] Of working with Congress on clean energy policy, Casten has said, "[T]he folks who really understand the energy system tend to be Republicans, and the folks who really understand environmental science tend to be Democrats. And there's a gap in talking to each other".^[26] "We have a PhD-level problem. And Congress is at a 6th-grade reading level", he has said.^[25]

Casten has introduced several bills related to energy policy, among them the Climate Risk Disclosure Act and the End Oil and Gas Subsidies Act.^[28][29] The Clean Industrial Technology Act of 2019 would have established a program to incentivize innovation in greenhouse gas emissions from manufacturing.^[30]

FERC issues

Casten has worked to increase the visibility of the Federal Energy Regulatory Commission (FERC), a federal agency with regulatory powers in the energy sector. In Congress, Casten has led efforts to "turbocharge FERC's profile" and to utilize the agency to promote the clean energy transition.^[31]

In 2021, Casten debuted a "Hot FERC Summer" campaign, a play on the phrase "hot girl summer" that rose to viral popularity in 2019.^[32] In 2022, Casten reworded the lyrics to Rihanna's 2016 single Work on the House floor to advocate for giving increased resources to FERC to allow it to "work".^[33]

Reparations

Casten is a sponsor of the Commission to Study and Develop Reparation Proposals for African-Americans Act. The bill would allow history books to go into more depth on African American struggles and set up a reparations commission for those with enslaved ancestors.^[34][35]

Voting rights

Casten voted for Ayanna Pressley's amendment to H.R. 1, the Voting Rights Act, which would lower the voting age to 16.^[36]

Abortion

Casten is an outspoken supporter of abortion rights.^[37][38] Following the Dobbs v. Jackson Women's Health Organization decision, Casten voted for H.R.8296, the Women's Health Protection Act of 2022,^[39] which would protect a person's ability to end a pregnancy and a healthcare provider's ability to provide abortion services.^[37]

Syria

In 2023, Casten voted against H.Con.Res. 21 which directed President Joe Biden to remove U.S. troops from Syria within 180 days.^[40][41]

Structural changes to make Federal government more representative

In the 118th Congress Casten co-sponsored three bills to restructure Congress and the judicial branches of the U.S. government to make them more representative:^[42]

• The Equal Voices Act would periodically adjust the number of Representatives in the House of Representatives so that each Congressional District would be computed by the population of the least populated state. Using the 2020 census, there would have been 138 more Representatives than present, each representing a district roughly the population of Wyoming.^[43]
• The Senate Reform constitutional amendment would add 12 new Senators elected at-large by ranked-choice voting from the entire electorate (including non-states such as District of Columbia). It would also add 12 presidential electors who would be pledged to vote according to the national popular vote.^[44]
• The Restoring Judicial Separation of Powers Act would restructure the federal courts and appeals process to make it more difficult for one party to game the system by stacking the courts.^[45]

Israel

Casten voted for a resolution in support of Israel following the 2023 Hamas attack on Israel.^[46][47]