Congressional Support for Aiding Ukraine Frays Amid Spending Battle

A strong and longstanding bipartisan consensus in Congress around providing huge sums to aid Ukraine’s war effort is beginning to fray as a pivotal counteroffensive against Russia is underway, and as Republicans bent on slashing federal spending gain traction in their efforts to limit or block future military assistance for Kyiv.

Right-wing House Republicans have long opposed U.S. support for Ukraine, but until recently they lacked the numbers to thwart any aid packages, which have sailed through Congress with the support of a critical mass of G.O.P. hawks — including the party’s top leaders — and Democrats. The bill that passed this month suspending the debt ceiling set spending limits that strengthened their hand, and increased the political pressure on Speaker Kevin McCarthy to keep a tight lid on federal expenditures.

It also intensified the skepticism to new aid for Ukraine among some progressive Democrats, who were angry that the fiscal agreement capped spending on domestic programs, such as education, housing and food assistance, while it allowed military funding to continue to grow. They are now hinting that any future assistance to Kyiv must be accompanied by more nonmilitary spending, a nonstarter with Republicans.

Since the Russian invasion, Congress has extended military and humanitarian assistance to Kyiv through a series of emergency spending measures totaling more than $100 billion. While the Biden administration has not yet asked for funds for the next fiscal year, Democratic and Republican congressional aides anticipate that the next request will be smaller, reflecting battlefield limitations and the political difficulties of justifying huge expenditures during an election cycle.

Mr. McCarthy, who last month publicly pledged his support for continued U.S. aid to Ukraine, changed his tune after he reached a compromise with President Biden on the debt limit, telling reporters that continuing to approve additional funds for Kyiv outside the normal budget would be “only blowing up the agreement.”

The comment reflected a schism that has been festering in the Republican Party between “America First” hard-liners, who have pressed to curtail aid to Ukraine and redirect those dollars toward things like protecting the U.S.-Mexico border, and traditional conservatives, who see funding Kyiv in the war as a vital investment in a fight to uphold a Western-style democracy.

That divide has been intensified by the debt ceiling deal, which enraged hard-right Republicans who said it did not do enough to slash federal spending and revolted on the House floor last week, showing their willingness to bring the chamber to a halt in the future if their demands were not met.

Their position has prompted a mild panic, particularly among Republican hawks in the Senate, who are now scrambling to find ways to free up funds for Ukraine within the spending caps set by the bill, or to forge a bipartisan deal to provide another round of emergency funding outside those limits.

“We’ve got to figure out where we can save in D.O.D.,” said Senator Joni Ernst, an Iowa Republican who sits on the Armed Services Committee, suggesting that if Congress could identify and redirect wasteful spending at the Department of Defense, or find cuts to nonmilitary foreign aid programs, “we can make some headway in funding for Ukraine.”

Other staunch Republican supporters of Ukraine’s military efforts argue that Congress has no choice but to approve additional funding for the war outside the regular budget, given the array of competing demands on limited U.S. defense dollars for things like modernizing infrastructure, hardening nuclear defenses and cyberdefenses, and deterring adversaries like China.

“I personally don’t believe that we can manage the Ukrainian assistance package that will be needed within the caps that have been prescribed,” said Representative Steve Womack, Republican of Arkansas and a member of the Appropriations Committee.

Whatever the ultimate size of the request, there would very likely be enough support in both chambers of Congress to pass an emergency spending bill for Ukraine if it reached the floor. A small number of left-wing Democrats have expressed unease about the continued fighting in Ukraine, but several have supported past assistance packages. Republicans who believe the United States should continue backing Ukraine’s war against Russia far outnumber the detractors.

But bringing up such legislation could be tricky for Mr. McCarthy, who is facing a recalcitrant band of anti-spending Republicans who have promised to wrest control of the floor from him if he crosses them.

The Ukraine conundrum complicates what was already expected to be a challenging summer, as House and Senate committees try to write legislation authorizing funds for the Pentagon and the military while adhering to the $886 billion spending limit that negotiators set for the 2024 fiscal year. That figure is a 3 percent increase over the current defense budget, but Republican defense hawks argue that it actually amounts to a cut in resources because of higher rates of inflation.

It is also many billions of dollars less than the combined amount the United States spent on its own defense and Ukraine’s war effort over the last year. That discrepancy prompted a last-minute revolt by some Republicans over the debt limit deal on the Senate floor, which stalled the package for hours as the senators demanded assurances that they would have future chances to supplement military funding, notwithstanding the spending limits contained in the compromise.

To address the concerns and cobble together the votes to pass the agreement, Senators Chuck Schumer, Democrat of New York and the majority leader, and Mitch McConnell, Republican of Kentucky and the minority leader, issued a joint statement insisting that the debt ceiling deal “does nothing to limit the Senate’s ability to appropriate emergency supplemental funds to ensure our military capabilities.”

But any move to add extra military spending could also run into resistance from liberal Democrats, who said the debt measure shortchanged domestic programs.

“We have a bill and a law now that put parameters around all of this,” said Representative Rosa DeLauro of Connecticut, the top Democrat on the Appropriations Committee and the author of past aid packages for Ukraine. This time around, she suggested, such a bill would be a nonstarter “unless there is a willingness to increase domestic spending at the same time.”

In the past, military assistance for Ukraine has been paired with money for disaster relief at home, a combination many congressional aides say will be a model for the next aid package. But with no guidance yet from the administration, which has signaled it wants to see how Ukraine’s counteroffensive progresses before coming to Congress with hard numbers, it is not clear how much additional aid will be necessary.

Last month, the Pentagon did an across-the-board reassessment of the value of the military assistance it had sent to Kyiv from U.S. stockpiles, coming up with an extra $3 billion worth of remaining authority that would be enough to last through September.

At that point, many lawmakers predict a substantial infusion will be needed.

“One of the things we’ve learned is the amount of ammunition, the amount of equipment destroyed, etc. — there will be a demand for that,” said Senator Jack Reed, Democrat of Rhode Island and the chairman of the Armed Services Committee.

“We’ll have to do a supplemental” spending bill, he added.