Tancredo introduced the Mass Immigration Reduction Act. The act would have imposed an indefinite moratorium on immigration to the United States. Under the act, only spouses and children of American citizens would be allowed to immigrate, which Tancredo estimated would amount to 300,000 immigrants annually. The moratorium would last for at least the first five years of the act and, after that, until such time as there were fewer than 10,000 illegal immigrants entering per year. When those conditions were met, immigration would only have been allowed at whatever level the president and both houses of Congress agreed would have no adverse impact on wages, housing, the environment, or schools. When last introduced in 2003, the bill had 11 cosponsors. Organizations that have endorsed Tancredo's bill include: NumbersUSA, Population-Environment Balance, Carrying Capacity Network, Federation for American Immigration Reform, Negative Population Growth, and the American Patrol. Tancredo introduced the bill in 2001 (H. R. 2712) and 2003 (H. R. 946). Tancredo did not re-introduce the bill in 2005. In 2007, he proposed an amendment to the U.S. Constitution to "establish English as the official language of the United States", (H.R. 19).