Dramatic losses in population in St. Louis in the 2010 Census contributed to Missouri losing a Congressional seat effective 2013.

[6] In addition, Carnahan supported programs to provide prison inmates with drug and alcohol addiction treatment.

[6] Carnahan also wanted to strengthen emission controls on all gasoline and diesel-powered engines, including cars, trucks, and SUVs.

[10] In addition, he supported international voluntary and mandatory emission targets to limit global warming.

[6] Carnahan has supported the interests of groups trying to protect the environment, such as the Defenders of Wildlife Action Fund.

[13] Carnahan wants tax credits to be offered to individuals and small businesses to offset the cost of insurance.

3962: Affordable Health Care for America Act in 2009,[14] Foreign Policy In January 2010, Carnahan partnered with Republican Congressman Joseph Cao of Louisiana to create the American Engagement Caucus, its stated purpose being the promotion of a multilateral foreign policy in which the United States works closely with other countries to address global problems.

America's security, economic, environmental, and moral interests are inextricably linked with those of the international community.

[17] Robin Carnahan, Russ's sister also has an F rating with the NRA-PVF, who backed her opponent in the 2004 election for Missouri Secretary of State.

"[19] Carnahan's first campaign for political office was in 1990, when he unsuccessfully ran for Congress in the 8th Congressional District against Republican U.S. Representative Bill Emerson, losing by 14 points, 57% to 43%.

Prior to challenging Emerson, by his own telling the then-32-year-old Carnahan had already "been active in government and politics for most of my adult life.

"[24] The Sikeston Standard-Democrat said, "Democrat Russ Carnahan has brought more mud into a congressional campaign than the days of Bill D.

"[25] According to the Rolla Daily News, "We have already heard enough from Carnahan, whose loose interpretation of Mr. Emerson's record is grossly misleading.

In the general election Carnahan faced Republican candidate William J. Federer, an author and Religious Right activist who had previously run against Gephardt on several occasions.

However, St. Louis's strong Democratic tilt (a Republican had not represented this district or its predecessors since 1953) helped Carnahan win with 53 percent of the vote.

[30] The new map merged all of St. Louis, including Carnahan's home, into the 1st District, represented by six-term Democrat Lacy Clay.

Carnahan challenged Clay in the primary for the redrawn 1st on August 7, 2012–the real contest in this heavily Democratic district–and lost by a landslide, 63% to 34%.

[31][32] Carnahan was mentioned as a possible candidate to fill a vacancy in the 8th District after Rep. Jo Ann Emerson stepped down in 2013.