She lamented to Boehner that he didn't fulfill her request to give Democrats have an equal voice in terms of issuing subpoenas and other procedural matters on the committee.
"Regrettably, the proposal does not prevent the unacceptable and repeated abuses committed by Chairman Issa in any meaningful way, and we find it fundamentally unfair," Pelosi wrote.
The Democratic leader is juggling several different goals when determining whether or not her party will boycott the panel. She's facing internal dissent from some members who want to participate, while leadership prefers to boycott. And she wants her party to appear reasonable in order to persuade the public that Republicans have ulterior motives in setting up the panel -- namely to attack the Obama administration and tarnish Hillary Clinton ahead of a possible 2016 presidential run.
Boehner, meanwhile, has also tried to appear as reasonable as possible, repeatedly insisting the panel will conduct a serious investigation rather than a partisan witch-hunt. "This investigation is about getting answers for the families of the victims and for the American people," he said Friday upon announcing the seven GOP members of the committee. "These members have each demonstrated a commitment to this goal, and I have confidence that they will lead a serious, fact-based inquiry."
The two leaders have met recently to see if the differences can be resolved.
"I am still hopeful we can reach an agreement," she wrote.
Added Pelosi's spokesman Drew Hammill: "The ball is in their court."