Wisconsin Republican Senator Ron Johnson called for transforming Medicare and Social Security from entitlements to budget items Congress debates annually, handing Democrats a potent attack line as they try to oust him in the November election.

Johnson, whose seat could determine Senate control, said Tuesday the structure of Medicare and Social Security, which are funded largely through dedicated payroll taxes, as entitlements keeps Congress from fixing programs that he said are going to go bankrupt while the national debt continues to go up.

“If you qualify for the entitlement, you get it no matter what the cost. And our problem in this country is that more than 70% of our federal budget is all mandatory spending,” he said on “The Regular Joe Show” podcast. “What we ought to be doing is we ought to turn everything into discretionary spending. So it’s all evaluated.”

Democrats in Congress and at the White House on Wednesday highlighted the remarks by Johnson, the only Republican running for re-election this year in a state won by President Joe Biden. He’s widely seen as the most vulnerable Republican incumbent in the midterm elections.

Senate Majority Leader Chuck Schumer said that Johnson “wants to put Medicare and Social Security on the chopping block. He has argued that the benefits which millions of Americans rely on every day shouldn’t be guaranteed.”

White House press secretary Karine Jean-Pierre cited Johnson using the same “chopping block” language at the daily White House briefing.

Both programs are aimed primarily at older Americans, who historically vote in higher proportions than other groups. The Social Security program, which provides monthly payments to retirees, in particular has been referred to as a “third rail” in US politics: touching it is likely to be politically fatal.

Johnson’s office didn’t immediately provide a comment on his remarks and Democrats’ response.

Johnson is poised to be renominated to run for a third term in next Tuesday’s Wisconsin GOP primary. Democrats have been coalescing around Lieutenant Governor Mandela Barnes as their challenger to Johnson. Barnes also seized on Johnson’s remarks, tweeting that the Republican “is trying to strip working people of the Social Security and Medicare benefits they’ve earned over a lifetime of hard work.”

This article was provided by Bloomberg News.