If, by ‘bi-partisan’ you mean two Republicans

MSNBC:

Bush said Miers withdrew because of a bipartisan effort in Congress to gain access to internal documents related to her current role as counsel to the president.

“It is clear that senators would not be satisfied until they gained access to internal documents concerning advice provided during her tenure at the White House — disclosures that would undermine a president’s ability to receive candid counsel,” Bush said. “Harriet Miers’ decision demonstrates her deep respect for this essential aspect of the constitutional separation of powers — and confirms my deep respect and admiration for her.”

Slate:

The fight over documents related to Miers’ work in the White House was the last straw. According to administration officials, Sens. Sam Brownback, R-Kans., and Lindsay Graham, R-S.C., were adamant that they would need documents—something, anything—to make up for her thin record and middling performance since her nomination. Miers’ questionnaire had been paltry. Her visits with senators had not gone well. At his Cabinet meeting Monday, Bush told his staff the documents represented a “red line” that he would not cross, setting the stage for the showdown.

Well they are from two different states…