2010: Voted against the DREAM Act amnesty.
The DREAM Act would have granted amnesty to illegal aliens under the age of 30 who have been in the United States for five consecutive years and came illegally to the United States before the age of 16. Such a reward for illegal immigration serves as an incentive for more illegal immigration.

2009: Voted to allow consideration of verification amendments to the health care reform bill Rep. Thompson voted against the rule to H.R. 3962, the Affordable Health Care for America Act. Despite high publicity about the big loopholes in the bill allowing illegal aliens to participate in many parts of the new federal health care plan, the Rules Committee brought a rule to the House floor that blocked a vote on any amendment giving the Members a chance to close the loopholes. NumbersUSA notified the Members of Congress that a vote FOR the closed rule would be graded as a vote to provide rewards and incentives for illegal immigration. In particular

2009-2010: Supported an amendment to deter illegal immigration and drug smuggling by removing lookout posts for smugglers.
Rep. Thompson supported the King amendment (250) to H.R. 2892, the 2010 DHS appropriations bill. This amendment requires Immigration and Customs Enforcement to remove the lookout posts constructed by drug smugglers, thereby making it more difficult for drug smugglers and reducing illegal immigration associated with illegal drug activity. This amendment passed 240-187-1.

2009-2010: Voted for an amendment to require DHS contractors to use E-Verify.
Rep. Thompson supported the King amendment (253) to H.R. 2892, the DHS appropriations bill. The amendment requires all DHS contractors and subcontractors to use the E-Verify system to verify the employment eligibility of their employees. The King Amendment would have essentially implemented an Executive Order signed by President George W. Bush requiring all federal contractors to use E-Verify that has continually been postponed by President Obama. Use of E-Verify is one of the most effective tools at keeping illegal aliens out of U.S. jobs. The amendment passed 349-84, and the bill was signed into law October 28th, 2009.