Congressional Democrats are sharply attacking a Republican budget plan for its changes to Medicare — even as Republicans criticize Democrats for not offering a plan.

Sen. Tim Johnson, D-S.D., singled out the Medicare changes Wednesday in a conference call with South Dakota reporters.

“The House Republican … budget proposal ends Medicare as we know it,” Johnson said.

The House proposal, authored by Rep. Paul Ryan, R-Wis., would change Medicare for those younger than 55 years old as they become eligible for the federal health insurance program. Instead of the current system, where Medicare is an insurance program that pays a percentage of seniors’ medical costs, Ryan’s proposal would instead give future seniors money to buy health insurance themselves from a list of approved insurers on a Medicare health insurance exchange.

People older than 55, or those enrolled in Medicare, would not see their program change.

Democrats argue that plan would leave seniors paying more in the end.

“This scenario would leave them on the hook to pay thousands out of pocket every year to pay for their health care,” Johnson said.

But Republicans said Johnson’s criticism was inaccurate.

“There isn’t a senior citizen in America, a senior citizen in South Dakota or anybody over the age of 55 who’s even impacted by the Ryan budget,” Sen. John Thune, R-S.D. said. “It does apply to people under 55. What it does is it guarantees them a benefit in the future which they otherwise won’t have because the program is destined to go bankrupt.”

The Senate voted against the Republican proposal Wednesday, with 52 Democrats — including Johnson — and five Republicans rejecting the plan. Forty Republicans, including Thune, voted for the plan.

The House of Representatives previously approved the plan 235-193, with Rep. Kristi Noem, R-S.D., voting yes.

Thune said the plan wasn’t perfect but that it would address the federal deficit over the long run by reducing Medicare costs, which are a major and growing part of federal spending.

“I don’t think the Ryan budget is the absolute perfect solution. But it is courageous,” Thune said.

Democrats, Thune said, don’t have room to criticize the Republican budget because they haven’t even offered their own budget.

“It at least makes an honest effort at trying to address the spending and debt problems the country has and at reforming entitlements,” Thune said of the Ryan plan. “People don’t agree with it, but show me your alternative. Right now, the Democrats don’t have one.”

Johnson said there was no point in passing a budget proposal that Republicans in the House would simply reject.

“The best opportunity for action — real action — on the budget proposal lies with the administration and Republicans and Democrats working together,” Johnson said.

He said he is putting his hopes on budget negotiations between leaders of both parties led by Vice President Joe Biden.

“We’ve tried all year to come together with some proposal that involves Republicans but the Republicans won’t play ball. We have no other choice but to send the ball over to Biden,” Johnson said.

Thune said that isn’t an excuse, especially given that Congressional Democrats didn’t pass a budget last year.

“My suggestion would be, work on a budget that can get 51 votes in the Senate,” he said. “I don’t know why you would go for 756 days — which is what it is now — not having even presented a budget to the United States Senate.”

Funding for the current fiscal year only passed last month, after tense negotiations between Democrats and Republicans that included the threat of a government shutdown if an agreement wasn’t reached.