WASHINGTON — Talks intensified Tuesday toward a potential end to the government shutdown, as the federal closure was on track to become the longest ever, disrupting the lives of millions of Americans.

But tensions also rose as senators from both parties, Republicans and Democrats, quietly negotiated the contours of an emerging deal. With a nod from their leadership, the senators are seeking a way to reopen the government, put the normal federal funding process back on track and devise some sort of resolution for expiring health insurance subsidies that are spiking premium costs from coast to coast.

“Enough is enough,” said Senate Majority Leader John Thune, the South Dakota Republican, as he opened the deadlocked chamber.

On day 35 of the federal government shutdown, the record for the longest will be broken after midnight. SNAP benefits have been interrupted for millions of Americans depending on federal food aid and hundreds of thousands of federal employees have been furloughed or are working without pay. Transportation Secretary Sean Duffy predicted there could be chaos in the skies next week if air traffic controllers miss another paycheck. Labor unions put pressure on lawmakers to reopen the government.

President Donald Trump has stayed largely on the sidelines, refusing to negotiate over the demands for health care funds until government reopens, and Democrats are wary of making any deal with Republicans unless it has approval from the White House.

Democratic senators emerged stone-faced from a two-hour discussion at the Capitol.

“We’re exploring all the options,” said Senate Democratic Leader Chuck Schumer afterward.

Trump abruptly invited senators from his own Republican Party for a private breakfast meeting Wednesday.

Election Day is seen as a turning point: Tuesday’s elections provide an inflection point, with off-year races that will show voter attitudes, a moment of political assessment many hope will turn the tide. Another test vote Tuesday in the Senate failed, as Democrats rejected a temporary government funding bill.

“These people are worth fighting for,” said Sen. Chris Murphy, D-Conn., about those experiencing rising health care costs.

Unlike the shutdown during Trump’s first term, when he fought Congress in 2018-19 for funds to build the U.S.-Mexico border wall, the president has been relatively quiet.

Trump threatens to halt SNAP food aid: But on Tuesday, Trump issued a fresh threat, warning he would halt food aid under the Supplemental Nutrition Assistance Program unless Democrats agree to reopen the government.

SNAP benefits “will be given only when the Radical Left Democrats open up government, which they can easily do, and not before!” Trump said on social media. That seemed to defy court orders to release the SNAP contingency funds.

White House press secretary Karoline Leavitt said later that the administration continues to pay out SNAP funding in line with court orders. But Democrats in the House and the Senate warned that Trump cannot be trusted to follow the law or keep his word.

“What message do you think it means when the president says, ‘I’m not going to release those funds’?” Rep. Debbie Dingell, D-Mich., asked. Democrats demanded the House reopen for negotiations.

Since House Speaker Mike Johnson sent lawmakers home in September, attention is on the Senate. There, the leadership has outsourced negotiations to a loose group of centrist dealmakers from both parties who have been quietly charting a way to end the standoff.