Warning of a "hasty, dangerous vote" on a last-ditch attempt to repeal and replace Obamacare, Democrats wrote a letter to the Congressional Budget Office asking for a comprehensive report on the cost and impact of the plan.

"Before votes are taken … the public needs a full understanding of the impact this legislation would have on hard-working families," House Minority Leader Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y., wrote Monday to CBO Director Keith Hall.

Democrats are eager to stir up opposition to the legislation proposed by Sens. Lindsey Graham, R-S.C., and Bill Cassidy, R-La., that would give states financial control and authority over the fate of Obamacare, which has suffered from soaring premiums and shrinking insurance markets.

Republicans have until the end of the month to use a 2017 budgetary tool that would allow them to pass the bill without a Senate filibuster by the Democrats.

While the proposal appears to be gaining support among GOP lawmakers, it lacks a full analysis by the CBO.

"A comprehensive CBO analysis is essential before Republicans force a hasty, dangerous vote on what is an extreme and destructive repeal bill," Democrats wrote to Hall. "Members of Congress and the American people need to know the full consequences of Graham-Cassidy before any vote."

Republicans are wary of CBO analyses because they were inaccurate about the impact of Obamacare and, in the case of the GOP replacement plans, have not incorporated the positive impact of yet-to-be-passed healthcare replacement plans.

Senate Majority Leader Mitch McConnell, R-Ky., has requested an analysis from the CBO on the plan, but the Senate could vote before a full report is available if the GOP rounds up enough support to pass it.