MANCHESTER, N.H. — Former Vice President Joe Biden's campaign won't say whether he stands by his 1996 vote for welfare reform. That vote, and his failure to own it or disown it, could quickly become an additional anchor on his flagging campaign after Tuesday's Democratic presidential primary here.

Biden, who blamed President Donald Trump on Saturday for the depths of poverty in the state, is expected to finish well out of first place in the primary, and he will need to rebound in the more racially diverse states coming up next — Nevada and South Carolina — if he hopes to resurrect his hopes of winning the nomination.

But the welfare law has had a disproportionate effect on the fortunes of black and Latino families across the country, including among African Americans in many of the Deep South states key to Biden's long-term strategy.

The only other presidential candidate who was in Congress when the law was enacted, Sen. Bernie Sanders, I-Vt., voted against welfare reform as a junior member of the House. That put Sanders on the same side as the overwhelming majority of black and Hispanic lawmakers.

Biden "fought alongside right-wing Republicans to pass so-called 'welfare reform,'" Sanders campaign co-chair Nina Turner wrote last month in an op-ed in South Carolina's The State newspaper, in which she accused Biden of having "repeatedly betrayed black voters." Sanders distanced himself from Turner, but the attack raised the prospect that the law will be revisited in the coming days.

A defining issue of its era, the bipartisan welfare reform compromise made massive changes to federal benefit programs for the poor, cut government spending and helped pave the way for President Bill Clinton's re-election by robbing Republican Bob Dole of a major issue.

The main title ended the Social Security Administration's cash-assistance entitlement program, Aid for Families with Dependent Children, or AFDC, and replaced it with the modern state block grant known as Temporary Assistance for Needy Families, or TANF, which has been capped at $17 billion annually ever since.

Nearly 25 years after Biden voted for it in the Senate, his campaign declined to say directly whether he stands by his vote.

Instead, a campaign spokesman e-mailed a long response to several questions posed by NBC News that explained the context of his position.

"When it became clear that welfare reform was going to move through Congress with bipartisan support — and with the support of the president — then-Senator Biden worked to make sure that the final bill reflected his progressive values by successfully maintaining funding for children's health and safety, supporting childcare, protecting Medicaid coverage for poor children, and preventing the block granting of Medicaid and Food Stamps," Biden spokesman Michael Gwin said in the message.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Biden voted for the final version after Clinton had vetoed two earlier attempts by congressional Republicans to enact measures with even deeper cuts to programs benefiting the poor. Biden's own alternative version of the bill, which was rejected by the Senate, included the provision replacing AFDC with TANF. Biden had previously voted for a non-binding measure expressing support for keeping AFDC as an entitlement, but he viewed that as a lost cause by the time the legislation was moving.

Gwin said Biden now wants to improve the country's social safety net if he wins the presidency.

"As President, Joe Biden will build on the successes of the Obama-Biden administration — like the Affordable Care Act — in strengthening and expanding our safety net and investing in disadvantaged communities by increasing Social Security benefits, tripling Title I funding for low-income schools, and implementing a host of other measures that will help ensure that Americans have an opportunity to work their way to the middle class and live with dignity," he said.

Biden spoke passionately Saturday night about handing out food to children and adults with his wife, Jill, and his grandchildren earlier in the day as he blamed President Donald Trump, who has proposed and begun to implement deep benefit cuts for federal subsidies benefiting the poor, for "making it so much harder in this country."

"To see them standing in line, huddled, no gloves, freezing to death, waiting to pick up a cardboard box, not able to pick it up, kicking it along the way so they could put bread in it, and they could put doughnuts in it," he said. "Watching women, a woman, with barely a sweater on, with a child in her arms, holding her child tightly, and you could see the tears coming down her eyes as she picked up bread. ... God, I thought to myself, this is the United States of America."

Download the NBC News app for breaking news and politics

On one level, there is an echo of Biden's role in the Clinton crime bill in his support for welfare reform. Both were measures important to Clinton's re-election that pitted liberal Democrats against centrists at the time and have become even more controversial within the party in the years since. But there are key differences, too.

Unlike the crime bill, which got significant support from lawmakers of color, there was no ambiguity for black and Hispanic Democrats about welfare reform. On its final trip through the House back then, 44 black or Hispanic Democrats voted "no," four voted "yes" and two did not vote. Sanders voted with the vast majority of black and Hispanic members.

"I am concerned because when many of those in this body speak of cutting destitute families off welfare, it is not really about the green buck but about the black face," Rep. Cardiss Collins, D-Ill., a member of the Congressional Black Caucus, said in December 1995 as the debate was heating up.

The law passed by more than 3 to 1 in the House as all but three Republicans and exactly half the Democratic caucus voted for it. In the Senate, Biden was one of 24 Democrats to vote for the law, with 21 voting against it.

Since its enactment, supporters have heralded the law for cutting federal spending — which was mandated — and the length of welfare rolls. But critics say that the poor have suffered for restrictive eligibility requirements and that states, afforded more flexibility in their use of federal dollars, have often diverted them from the direct cash payments that helped families.

"When cash assistance disappears, what does this mean?" said Ife Floyd, a senior policy analyst at the Center for Budget and Policy Priorities who studies family income support. "Parents who have lost jobs or are fleeing domestic violence have less financial support to pay the rent, buy food or put gas in their car. They basically have less support to maintain stability after a crisis. And black families in need are more likely to experience that instability."

The data show that both sides are right: Fewer poor families are getting federal aid.

"Nationally, TANF has provided less and less of support to families experiencing poverty since the program started in 1996," Floyd said. "In 2018, the program served 22 families for every 100 in poverty, down from 68 in 1996."

Gwin, the Biden spokesman, also declined to say directly whether Biden believes TANF has been successful in place of AFDC.

But Michael Moore, a close friend of Sanders who often speaks at his campaign rallies, spoke to NBC News about the issue outside the New Hampshire Democratic Party's McIntyre-Shaheen 100 Club dinner in Manchester on Saturday night.

"It was cruel," Moore said of the law, which was enacted when he was living in Flint, Michigan, where poverty rates have been persistently high.

He said Biden was "not getting the right advice" on how to address his record.

"It's OK to say, 'I voted for it for this reason, we needed the money for this specific purpose, whatever,'" Moore said. "That's all Biden has to say. I think he's a good guy. He has a good heart."

Biden has relied so far on Democrats' believing that his values line up with theirs, even though much of his record is out of step with the party's modern platform. At a time when income inequality, generational poverty and racial disparities are all animating issues for party voters, it's hard to imagine that he will be able to go much further without taking a position on his own welfare reform vote.