WASHINGTON (AP) — Overcoming a week of setbacks, the Senate on Thursday voted to begin work on a package of wartime funding for Ukraine, Israel and other U.S. allies. But doubts remained about support from Republicans who earlier rejected a carefully negotiated compromise that also included border enforcement policies.

Senate Majority Leader Chuck Schumer called the latest vote a “good first step” and pledged that the Senate would “keep working on this bill -- until the job is done.”

The 67-32 vote was the first meaningful step Congress has taken in months to approve Ukraine aid, but it still faces a difficult path to final passage. Continued support from GOP senators is not guaranteed, and even if the legislation passes the Senate, it is expected to be more difficult to win approval in the Republican-controlled House, where Speaker Mike Johnson, R-La., has been noncommittal on the aid.

The Senate prepared for a days-long slog to reach a final vote. Leaders had not agreed to a process to limit the debate time for the bill as Republicans remained divided on how to approach the legislation.

The $95 billion package is intended to show American strength at a time when U.S. military troops have been attacked and killed in Jordan, allies including Ukraine and Israel are deep in war and unrest threatens to shake the global order. It is also the best chance for Congress to replenish completely depleted military aid for Ukraine — a goal shared by President Joe Biden, Schumer and Senate Republican leader Mitch McConnell.

After the collapse this week of a bipartisan agreement to include border policy changes in the package, Schumer salvaged $60 billion in aid for Ukraine, as well as roughly $35 billion for Israel, other allies and national security priorities in the current legislation.

But Senate Republicans were fractured and frustrated as they huddled Thursday morning to discuss their approach to the legislation and struggled to coalesce behind a plan to assert their priorities. Still, Schumer forged ahead to the noon-hour vote, essentially daring the Ukraine supporters within the GOP to vote against the aid.

Schumer's push worked as the vote to begin debate on the new package cleared with 17 Republicans along with Democrats voting to move forward. Sen. Bernie Sanders, an independent from Vermont who opposes much of the aid for Israel, voted against it.

Some in the Senate vowed to do everything they could to delay final action.

“I’ll object to anything speeding up this rotten foreign spending bill’s passage,” said Sen. Rand Paul, a Kentucky Republican, on X.

The U.S. is already out of money to send missiles and ammunition to Kyiv, just as the nearly two-year-old war reaches a crucial juncture. Ukraine supporters say the drop-off in U.S. support is already being felt on the battlefield and by civilians. Russia has renewed its commitment to the invasion with relentless attacks.

“There are people in Ukraine right now, in the height of their winter, in trenches, being bombed and being killed,” said Sen. Thom Tillis, R-N.C.

While military support for Ukraine once enjoyed wide bipartisan support in Congress, an increasing number of Republicans in the House and Senate have expressed serious reservations about supporting a new round of funding for Ukraine. Following the lead of Donald Trump, the likely GOP presidential nominee, they see the funding as wasteful and argue that an end to the conflict should be negotiated.

Biden has made halting Russian President Vladimir Putin's invasion a top foreign policy priority and last year requested a sweeping funding proposal to replenish aid for Ukraine and Israel, as well as to invest more in domestic defense manufacturing, humanitarian assistance and managing the influx of migrants at the U.S.-Mexico border.

The $95 billion package proposed by Democrats this week would send $14 billion in military aid to Israel, provide further funding for allies in Asia, and allot $10 billion for humanitarian efforts in Ukraine, Israel, Gaza and other places.

The revamped package includes legislation to authorize sanctions and anti-money laundering tools against criminal enterprises that traffic fentanyl into the U.S.

Supporters of the national security package have cast it as a history-turning initiative that would rebuff both Russia's incursion in Europe and Chinese President Xi Jinping's ambitions in Taiwan and Asia.

“Failure to pass this bill would only embolden autocrats like Putin and Xi who want nothing more than America’s decline,” Schumer said.

Republicans had initially demanded that the package also include border policy changes, arguing that they would not support other countries' security when the U.S. border was seeing rampant illegal crossings. But after months of round-the-clock negotiations on a bipartisan compromise intended to overhaul the asylum system with faster and tougher enforcement, Republicans rejected it as insufficient.

Some Republicans, even traditional supporters of Ukraine, refused to give up demands for border measures.

“It’s pretty dire if you have to negotiate with Putin to give up significant territories,” said Sen. Marco Rubio, R-Fla. “And I think it would also have an impact on how allies around the world view us and our reliability.”

But he insisted, “The point is we can address that... All I ask is the president enforce our immigration laws and he’s just grotesquely ignoring this, on purpose."

A number of Republicans appeared determined to mount another push for border legislation and suggested that the contours of the bill unveiled on Sunday could still be modified and made more strict. During one moment on the Senate floor, Sens. Lindsey Graham, a South Carolina Republican, and Kyrsten Sinema, an Arizona independent who crafted the border proposal, entered into a testy exchange.

“I am not going to put Ukraine, Israel, or anybody else ahead of America,” Graham said. “I am going to try to create an outcome where the bill gets through the House. It's got to get through the House."

Sinema responded by pointing out that Graham voted against opening debate for the border and Ukraine deal on Wednesday. She said that had Republicans supported that bill, it could have made it easier to add policies they wanted to the legislation.

“If we had wanted to have a robust debate, an openness to an open amendment process, the time to do that would have been yesterday,” Sinema said.