U.S. Sen. Michael Bennet said Wednesday that he plans to keep pushing to make permanent the expanded child tax credit he’s long championed — beyond the four additional years the Biden administration is proposing.

“This is the beginning of a legislative process, and I hope at the end of it — I don’t just hope, we’re going to fight like hell to make sure that we make it permanent,” Bennet told MSNBC’s Stephanie Ruhle on Wednesday after details of President Joe Biden’s $1.8 trillion American Families Plan emerged ahead of the president’s first speech to a joint session of Congress later that night.

Bennet and a group of influential Democratic lawmakers — including U.S. Sens. Sherrod Brown of Ohio and Cory Booker of New Jersey and U.S. Rep. Rosa DeLauro of Connecticut, chair of the House Appropriations Committee — had been urging the administration to include a permanent extension in the proposal, dubbed the “human infrastructure” package, though some elements of the new benefit did make it into the White House plan.

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The expanded child tax credit is a signature Bennet issue analysts say will cut the child poverty rate nearly in half starting this year after a one-year version was included in the massive pandemic relief legislation Biden signed last month.

The new version increases an existing $2,000-per-child tax credit to $3,600 for children under 6 and $3,000 for children up to age 17 — adding 17-year-olds for the first time. It also makes the benefit fully refundable, meaning parents can get the money whether they make enough to file taxes or not. In addition, the Treasury Department is planning to start issuing monthly checks for $250 or $300, depending on the child’s age, starting in July rather than paying out a lump sum at tax time, a feature supporters say will go a long way to helping families make ends meet.

“President Biden can unify the country and earn the confidence of the American people by responding to their needs. He took a huge first step-in that direction with the American Rescue Plan,” Bennet said Tuesday in a news conference. “We need to go a step further and make those extensions permanent this year. It’s our job to seize this moment and finally make the long-term investments in the American people that we’ve put off for far too long.”

“Kids don’t grow up in five years,” said U.S. Rep. Suzan DelBene, a Washington Democrat, arguing for the permanent extension. “Parents need predictability to plan for their future over the long term.”

Other Democrats said extending it only through 2025 risks its eventual elimination, if Republicans control the House, Senate or White House.

Bennet said Wednesday it’s his top priority as Biden’s legislation begins to move, though he acknowledged that the administration was balancing competing proposals when it came up with the package.

“My hope is that during this legislative process, we’re going to be able to demonstrate that there’s incredible support for this proposal to cut childhood poverty in half,” he said.

“No one knows — the White House doesn’t know, I don’t know — what it’s going to take to pass a bill through the Congress of this size and, in the end, what it’s going to contain. We’re going to have to put together a really interesting and unusual coalition to do it, but we need to do it because we have utterly under-invested in this country for decades, and this is our opportunity to start making up for that.”

Other elements of the Biden package include paying for preschool for 3- and 4-year-olds and making community college tuition-free. The plan would also provide childcare assistance and fund a national family and medical leave program, make an expansion of the Earned Income Tax Credit permanent and help recruit and educate teachers.

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The administration proposes paying for the package with tax increases on those with very high incomes, ending tax breaks for hedge fund managers and certain real estate investors and beefing up IRS enforcement to collect more taxes due from the wealthy.

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