President Biden is represented by Lauren Underwood in the movie Juliet

President Joe Biden campaigned for suburban Democrats in Joliet on Saturday, the latest campaign weekend visit to what has been a staunchly blue state, underscoring concerns among national Democrats that Republican wins in several races could give the party control of Congress on the day elections.

In his last-minute speech, which echoed his themes at stops that also included California, New York and Pennsylvania, Biden warned that Republicans would try to cut Social Security and Medicare if they take the House and Senate.

“These programs do something so basic, but so important,” he told about 300 people in the gymnasium at Jones Elementary School in Joliet. “After working hard for decades, people deserve to retire … with dignity.”

Citing statements from Republican senators Rick Scott of Florida and Ron Johnson of Wisconsin, Biden said the GOP wants Social Security and Medicare to face a reauthorization vote every five years, leaving longstanding programs for the elderly permanently vulnerable to liquidation.

“It’s a robust guarantee and a tough commitment,” Biden said of Social Security. “Generations of Americans have relied on this for decades, and it’s working.”

House Republican Leader Kevin McCarthy, D-Calif., who is poised to become House speaker if the GOP takes control, said during a campaign visit to Oak Brook on Friday that the party would not cut Social Security or Medicare if it wins a majority on Tuesday .

The president’s visit comes as national Republican and Democratic leaders gather in the Chicago area in the days before the midterm elections, raising funds and speaking on behalf of local candidates in House races.

McCarthy spoke on behalf of Orland Park Mayor Keith Peckau, a Republican seeking to unseat Democratic U.S. Rep. Sean Kasten in the tightly contested Illinois 6th District. Kasten and Democratic Sen. Dick Durbin held a last-minute campaign event in a hallway at the same hotel as Peckau’s fundraiser.

Vice President Kamala Harris planned to campaign in Chicago on Sunday with Democratic Governor J. B. Pritzker and US Senator Tammy Duckworth, who are both running for re-election.

Biden arrived in Chicago Friday night and spoke at a fundraiser for Kasten and Rep. Lauren Underwood of Naperville in Rosemont, and expressed optimism about Tuesday’s election.

“Folks, I don’t believe we’re in trouble,” Biden said. “I think we will win. I really do.”

But he soon added, “If we lose the House and the Senate, it’s going to be a terrible two years. The good news is that I will have veto power.’

Biden’s efforts on Saturday were aimed at endorsing Underwood, a two-term Democratic congresswoman.

“She got 10 pieces of legislation through her first term alone,” Biden said of Underwood, praising her earlier career as a nurse.

Electing House Democrats will protect the Deflation Act, a big spending bill that calls for investments in sustainable energy infrastructure and manufacturing and tax increases on corporations, Biden said.

Underwood spoke in front of Biden and U.S. Senators Dick Durbin and Tammy Duckworth, praising the Inflation Reduction Act and criticizing Republicans for the same issues on executive benefits.

“They don’t have a serious plan to lower health care costs, to fight inflation, or to stop price gouging at the gas station or the grocery store,” she said.

Republicans have argued that the Inflation Reduction Act promotes inflation by overspending and have called repealing the legislation a priority. But Biden argued that the act would soon lower health care costs by allowing Medicare to negotiate lower drug prices with drug companies and capping the price of insulin.

“For years, Big Pharma has prevented us from negotiating,” Biden said. “Not this year. We have finally defeated Big Pharma.”

As Democrats grapple with an inflationary economy, Biden has argued that the cost of living for Americans will rise if Republicans are elected because welfare plans that support people financially will be cut and taxes on corporations will be cut.

Outside the event, protesters waved flags proclaiming former President Donald Trump and used profanity to mock Biden. The President, promising continued support for social security and medical care, noted their presence during his speech.

“I like these signs when I came – ‘Socialism.’ Give me a break. What idiots,” said Biden.

Scott Grider of Oswego, Underwood’s Republican challenger, criticized the president’s comment as “offensive.” He visited the protesters and also held a separate rally at a nearby house, he said.

“When the president of the United States calls out, that means we’ve really sunk to a new level,” said Grider, who chairs the Kendall County Council. “People are frustrated because Washington isn’t listening, and that’s why we’re growing right now.”

Grider said that if elected, he would seek to reduce government spending, but not to cut Social Security or Medicare.

jsheridan@chicagotribune.com