State Medicaid directors voiced their opposition Thursday to the latest effort in the Senate to repeal the 2010 health care law.

The National Association of Medicaid Directors, a group that represents the directors of all 50 states, urged Senate Republicans to reconsider their support of the new repeal bill sponsored by GOP Sens. Lindsey Graham of South Carolina and Louisiana’s Bill Cassidy.

The so-called Graham-Cassidy bill would “fail to deliver on our collective goal of an improved health care system,” the directors wrote, because of complications with how it erases federal subsidies for Medicaid expansion and those seeking medical coverage and instead dishes out huge block grants to states on an individual basis.

The policy change would be “the largest intergovernmental transfer of financial risk from the federal government to the states in our country’s history,” the NAMD wrote. Republican senators argue the individual block grants would grant states more control and flexibility to tailor their health care system to their specific needs.

House Speaker Paul D. Ryan of Wisconsin has expressed his support for the bill and said the House would vote on it if it made it out of the Senate.

Republicans in Congress have campaigned for the better part of a decade on the promise to repeal the 2010 health care law. But they’ve squandered every opportunity to capitalize on that promise so far this summer despite holding a majority in both chambers and the backing of President Donald Trump.

Graham-Cassidy is the Republicans’ “best last chance to get repeal and replace done,” Ryan said earlier in the week.

Majority Leader Mitch McConnell indicated Wednesday that the chamber could vote on the bill as soon as next week.

“It is the leader’s intention to consider Graham-Cassidy on the floor next week,” Don Stewart, the Kentucky senator’s spokesman, said in an email.

Medicaid directors expressed concern that GOP senators are not reserving enough time to debate and gather input on Graham-Cassidy.

“Any effort of this magnitude needs thorough discussion, examination and analysis, and should not be rushed through without proper deliberation,” they wrote, noting that the legislation would not yet have a full CBO score by the time senators plan to vote on it.

“With only a few legislative days left for the entire process to conclude, there clearly is not sufficient time for policymakers, Governors, Medicaid Directors, or other critical stakeholders to engage in the thoughtful deliberation necessary to ensure successful long-term reforms.”

The NAMD is also worried Graham-Cassidy underestimates the resources state Medicaid programs would require to properly plan and implement the new policies so programs are ready to go by their scheduled start date of January 2020.

“The scope of this work, and the resources required to support state planning and implementation activities, cannot be overstated,” the directors said.

Without adequate federal funding, they added, “the vast majority of states” will not be prepared to operate their Medicaid program within the two-year time frame.

“We encourage Congress to revisit the topic of comprehensive Medicaid reform when it can be addressed with the careful consideration merited by such a complex undertaking.”