The group, led by Rep. Barbara Lee, D-Calif., asked Mukasey in a letter what he was doing to be certain President George Bush follows Congress' ban on establishing a permanent U.S. military base presence in the Middle Eastern country, The Hill reported Friday.
Congress included the ban in its 2008 Defense Department authorization bill. When Bush signed the measure last month, he called the ban unconstitutional.
"Provisions of the act ... purport to impose requirements that could inhibit the president's ability to carry out his constitutional obligations," Bush said in a signing statement.
Lee and the 45 co-signers also expressed doubts about the agreement Bush and Iraqi Prime Minister Nouri al-Maliki signed in November that pledged U.S. support for Iraq's security against internal and external threats.
"In light of such contradictions," the letter read, "we would like to learn precisely what is being done to make certain that permanent military bases are not being planned or constructed in Iraq and how the prohibition in law is being observed and overseen by the Bush administration.