The Democratic party’s most powerful voices warned that abortion, social security and democracy itself are at risk as they laboured to overcome fierce political headwinds over the final weekend of the 2022 midterm elections.

“Sulking and moping is not an option,” former president Barack Obama told several hundred voters in Pittsburgh on Saturday. “On Tuesday, let’s make sure our country doesn’t get set back 50 years.”

Later in the day, President Biden shared the stage with Obama in Philadelphia, the former running mates campaigning together for the first time since Biden took office. In neighbouring New York, former president Bill Clinton – largely absent from national politics in recent years – was also out defending his party.

Before arriving in Pennsylvania, Biden was dealing with a fresh political storm after upsetting some in his party for promoting plans to shut down fossil fuel plants in favour of green energy. While he made the comments in California the day before, the fossil fuel industry is a major employer in Pennsylvania.

Senator Joe Manchin, a Democrat from West Virginia and chair of the Senate energy and natural resources committee, said the president owed coal workers across the country an apology. He called Biden’s comments “offensive and disgusting”.

Former president Donald Trump was also campaigning on Saturday, finishing the day at a rally in south-western Pennsylvania where he claimed Biden had “resumed the war on coal – your coal”.

The White House said Biden’s words were “twisted to suggest a meaning that was not intended – he regrets it if anyone hearing these remarks took offence”. He was “commenting on a fact of economics and technology”.

Biden, Trump, Obama and Clinton – four of the six living presidents – focused on north-eastern battlegrounds on Saturday, as the parties sent out their biggest names to deliver a critical closing argument. Polls across America will close on Tuesday, but more than 36 million people have already voted.

Democrats are deeply concerned about losing their narrow majorities in the House and Senate, amid surging inflation and widespread economic concerns. History suggests that Democrats, as the party in power, will suffer significant losses in the midterms.

The attention on Pennsylvania underscores the stakes in 2022 and beyond for the tightly contested state. The Senate race could decide the overall Senate majority, and with it, Biden’s agenda and judicial appointments for the next two years. The governor’s contest will determine the direction of state policy and control of the state’s election infrastructure heading into the 2024 presidential contest.

Biden’s speech in Pennsylvania ran through a grab bag of major legislative achievements, while warning that abortion rights, voting rights, social security and Medicare are at risk should Republicans take control of Congress this week.

The president highlighted the Inflation Reduction Action, passed in August by the Democratic-led Congress, which includes several health care provisions popular among older adults.