Bipartisanship can also be between two opposite groups (e.g. liberal and conservative) to agree and determine a plan of action on an urgent matter that is of great importance to their voters.
Bipartisan is also a code word used by politicians to assure the other major party shares the blame for bad decisions and bad legislation. See also FISA, and the Patriot Act. Also reference how bipartisan agreements are used to assure the two major parties remain the only ones to have significant power and control over a system of government. See Ohio Revised Code.