Shimkus has focused on energy issues during his time in Congress, becoming a leading conservative voice on global warming, drilling policy and alternative fuels.
He supports lifting the ban on offshore drilling, allowing oil exploration in the Arctic National Wildlife Refuge, building the Keystone XL pipeline between Canada and the U.S. and developing oil shale in the Rocky Mountains.
Shimkus supported legislation in 2011 that gives the states the power to regulate coal ash from power plants as if it were municipal garbage, pre-empting pending federal regulations from the Environmental Protection Agency that could be much tougher.
"The results of EPA's regulations would have been devastating on the effects of jobs, higher utility rates at home, and cripple a very successful emerging biproducts industry," he said at the time.
Long an opponent of those who believe in global warming, Shimkus protested the Environmental Protection Agency's 2009 classification of carbon dioxide and other greenhouse gases as air pollutants, asking, "Does EPA propose we stop breathing?"
Shimkus has also questioned the need for action on global warming on the grounds that the Bible says God promised Noah the earth would not be destroyed by a second flood.
He worked successfully to qualify the soybean-based diesel fuel blend B-20 for an alternative fuels program, and he voted with the House majority to approve a plan to store the nation's nuclear waste at one place, Nevada's Yucca Mountain. He also opposed including parts of the Illinois River in the American Heritage Rivers program, leading the program to reject the entire river.
When he was elected in 1996, Shimkus promised to serve only six terms. But when the time came for him to step aside, he decided to run again. He was elected to his eighth term in 2010.
Shimkus joined five of his Illinois GOP colleagues in spring 2010 in asking the Illinois attorney general to file a lawsuit to block implementation of the federal health care reform bill, saying it is unconstitutional and that the state cannot afford expanded Medicaid payments. Attorney General Lisa Madigan declined.
Shimkus was head of the board that oversees the congressional page program on Capitol Hill when a scandal unfolded in 2006 involving then-Rep. Mark Foley, who sent sexually suggestive e-mails to young men involved in the program.
The House Ethics Committee said it found no evidence members of Congress other than Foley had violated rules. But the committee noted that Shimkus had told another page program board member that he withheld information about Foley's messages out of fear that "it would be blown out of proportion." Foley resigned in September 2006.
Shimkus has worked to oppose abortion and to limit minors' access to inappropriate material on the Internet. His opposition to so-called partial-birth abortions has helped him solidify support and given him increased clout to fight for other issues.