DENVER (CBS4) – Gov. John Hickenlooper claims a Republican plan to overhaul health care will cost Colorado around $1 billion.

Under Obamacare, 30 states — including Colorado — expanded Medicaid enrollment because the federal government agreed to foot the bill — at least initially. But under the Republican plan, in three years Colorado could be on the hook for the entire cost.

(credit: CBS)

When Colorado decided to expand Medicaid coverage three years ago nobody anticipated how big of an expansion it would be. The state added just over 400,000 people to its rolls.

Currently, more than a million Coloradans are on Medicaid and the state is suddenly faced with the prospect of paying up to $1 billion to continue to cover them all after the newly released Republican health plan called for phasing out the Medicaid expansion in three years.

CBS4’s Shaun Boyd interviews Gov. John Hickenlooper (credit: CBS)

“I don’t see how you can do this plan without significantly rolling back the number people that have coverage,” Hickenlooper told CBS4 Political Specialist Shaun Boyd.

Hickenlooper says that will drive up costs for all Coloradans, but the Republican president of the Colorado Senate Kevin Grantham says it’s not the GOP health plan to blame.

“We warned people back then, ‘This is the cliff that’s coming,'” Grantham said.

Under Obamacare, the federal government paid the full cost of the expansion initially, and then required the state to start covering an increasingly larger share of the cost.

Sen. Kevin Grantham (credit: CBS)

“We have to look at serious reforms when comes to Medicaid enrollment, and who’s on, who’s not,” Grantham said.

The governor says it’s also time states played a bigger role in the reforms.

“I talked to John Kasich, who’s a Republican governor from Ohio … we both agree if you got … three or four Republican governors and three or four Democratic governors; let us sit down and work through this — we’re the ones who implemented this stuff,” Hickenlooper said.

It’s still unclear if the Republican health plan can pass the Republican controlled Congress. Colorado’s U.S. Sen. Cory Gardner is among a group of Republicans who — while convinced the Medicaid expansion is unsustainable — are also concerned about changes to the program that serves the poorest Americans.