Democratic senators are pleading with President Obama to abandon his proposal to trim Social Security benefits before it becomes a liability for them in the midterm elections.

The president proposed a new formula for calculating benefits in his budget last year, in hopes that the olive branch to Republicans would persuade them to back tax increases in a broader fiscal deal.

But Democratic lawmakers say Obama should shelve the idea now that they are facing a difficult midterm election where they need to turn out the liberal base to preserve their Senate majority.

“I’m not sure why we should be making concessions when the Republicans show absolutely no willingness to do the same,” said Sen. Chris Murphy (D-Conn.).

Democrats acknowledge it may be awkward for Obama to rescind his proposal, but say it would unwise of him to repeat the offer in the budget that is due out next month.

“I think it’s difficult for the president to pull it back after he already floated it but I would love to see it shelved until Republicans show they’re actually going to do something on their side of the ledger,” Murphy said.

Obama proposed nearly $1 trillion in spending cuts in his budget, including a switch to using the Chained Consumer Price Index (CPI), which liberal policy experts estimate could cost seniors thousands of dollars in benefits over their lifetimes.