"After the Sept. 11, 2001, terrorist attacks, Gen. Clark counseled clients on how to pitch commercial technologies to the government for homeland-security applications. One is Acxiom Corp., based in Gen. Clark's hometown of Little Rock, Ark., where he formally launched his campaign Wednesday. He joined the board of the Nasdaq-traded company in December 2001, as the company started to market its customer-database software to federal agencies eager to hunt for terrorists by scanning and coordinating the vast cyberspace trove of citizen information.

"He has made efforts at putting us in contact with the right people in Washington ... setting up meetings and participating in some himself," says Acxiom Chief Executive Charles Morgan. "Like all of us around 9/11, he had a lot of patriotic fervor about how we can save our country."