Senate Democrats put salvaging an aid bill for Israel and Ukraine on hold for at least a day.

Senate Democrats, pressing to advance a stand-alone bill to send tens of billions of dollars to Israel and Ukraine after Republicans blocked a compromise that would have paired the aid with stringent border security measures, promised a Thursday vote on the alternative.

In a day of whiplash on Capitol Hill, Democrats on Wednesday pivoted to salvage the aid from becoming a casualty of former President Donald J. Trump’s political campaign. But after hours of stalemate, Senator Chuck Schumer, Democrat of New York and the majority leader, announced that senators needed more time to agree on how to move forward on that alternative, which Democrats and Republicans alike said they hoped would be successful.

Mr. Schumer had hoped for a quick vote on Wednesday on what he called his “Plan B” for reviving the aid package after the border deal failed. But by Wednesday evening, action had stalled, as Senate Republicans slow-walked business on the floor while they regrouped. They held open a procedural vote for hours as they sought assurances from Democrats that if they voted to allow the stripped-down aid bill to move forward, they would be allowed to propose changes.

After 7 p.m., Mr. Schumer said the Senate was recessing to “give our Republican colleagues the night to figure themselves out.”

Despite the delay, there were glimmers of hope that the package of aid for Ukraine and Israel would eventually move forward. A bipartisan vote to advance the aid package would represent a remarkable turnaround after months of stalemate and likely put the measure on track for passage in the Senate within days.

The measure would send $60.1 billion to Ukraine for its war against Russian aggression, $14.1 billion in security assistance for Israel and $10 billion in humanitarian aid for civilians of global crises, including Palestinians and Ukrainians.

The effort to get the legislation back on track came after Republicans blocked a bill that paired the foreign aid with stringent border security measures they had demanded. That plan, hashed out over four months of painstaking bipartisan negotiations, hemorrhaged Republican support after Mr. Trump vocally opposed it. It failed on a 50-to-49 vote, falling short of the 60 votes it would have needed to advance, as all but four Republicans voted to reject it.

Even if Democrats succeed in resurrecting the aid bill in the Senate, it still faces stiff headwinds in the Republican-led House, where right-wing lawmakers are opposed to sending additional assistance to Ukraine. Some have even threatened to oust Speaker Mike Johnson if he brings any bill to the floor that includes it.

Mr. Johnson would not say Wednesday morning whether the House would take up the stand-alone national security bill, if and when it passed the Senate. On Tuesday night, Republicans failed to push through a $17.6 billion bill to send military assistance only to Israel, a failure that Mr. Johnson tried to pin on Democrats.

Karoun Demirjian contributed reporting from the Capitol.