With multiple candidates fading away in the polls, the Democratic primary race once again looks like a two-way contest between former Vice President Joe Biden and independent Vermont Sen. Bernie Sanders. Now, with less than 30 days until the Iowa caucuses, both candidates are drawing contrasts and aggressively pitching themselves to voters.

In a new interview with CNN’s Anderson Cooper on Monday, Sanders took the gloves off, hammering his closest competitor, according to The Hill. Contrasting his record with Biden’s, Sanders attacked the central premise of the former vice president’s candidacy: perceived electability.

For months, Biden has been pitching himself to voters as the most electable candidate; the only Democrat in the race capable of beating President Donald Trump. Nothing could be further from the truth, according to Sanders, who hammered away at Biden’s support for offensive wars and opposition to welfare programs.

“Joe Biden voted and helped lead the effort for the war in Iraq, the most dangerous foreign policy blunder in the modern history of this country,” he began.

Sanders also pointed out that Biden supported NAFTA, a trade agreement that cost the United States “millions of jobs,” before moving on to the former vice president’s opposition to numerous entitlement programs.

“Joe Biden has been on the floor of the Senate talking about the need to cut Social Security or Medicare or Medicaid,” Sanders said, in an apparent attempt to appeal to seniors supportive of the Delaware Democrat.

The Vermont independent then went after Biden for supporting a 2005 bankruptcy bill, which — critics claim — favored credit card companies over ordinary Americans. The bill, Sanders said, “has caused enormous problems for working families.”

Because of his voting record, Sanders concluded, Biden would be unelectable in key battleground states the Democratic Party needs to win back in order to defeat Trump.

“Do you think that’s going to play well in Michigan, Wisconsin or Pennsylvania?” he asked.

“I just don’t think that that kind of record is going to bring forth the kind energy we need to defeat Trump.”

On the campaign trail, Biden has made a conscious effort to defend his voting record, alternating between acknowledging his mistakes and denying them. This Saturday, Biden was confronted about his support for the Iraq War, only to claim to have opposed former President George W. Bush’s military effort from the “very moment” it began. As fact-checks have shown, Biden strongly supported the war before and after it began.

Having surged in early state polls and raised more money than anyone else in the race, Sanders now reportedly faces strong opposition from the Obama wing of the Democratic Party, which remains supportive of Biden.