 Walker has presided over such notable cases as lawsuits over NSA warrantless surveillance; the "Apple Computer, Inc. v. Microsoft Corporation" copyright infringement case; the breach of TD Ameritrade's customer information database Clint Reilly's antitrust litigation over the Hearst Corporation's purchase of the "San Francisco Chronicle"; and Oracle's merger/hostile takeover of PeopleSoft, which was approved despite Justice Department opposition.On January 11, 2010, Walker began hearing arguments in "Perry v. Brown".The case was a federal-constitutional challenge to California Proposition 8, a voter initiative constitutional amendment that eliminated the right of same-sex couples to marry, a right which had previously been granted after the California Supreme Court found that Proposition 22 was unconstitutional.