A GoFundMe campaign received more than $6 million in contributions for a wall along the U.S.-Mexican border – but merely raising the money isn’t enough to ensure that it can be used for President Donald Trump’s long-touted goal.

The campaign, “We The People Will Fund The Wall,” was started by veteran Brian Kolfage, a Purple Heart recipient and triple amputee who lives in Florida.

“As a veteran who has given so much, 3 limbs, I feel deeply invested to this nation to ensure future generations have everything we have today,” Kolfage wrote on the campaign’s page. Kolfage, tired of inaction on the wall, started the campaign Sunday and began promoting it Monday.

The goal of the campaign is to raise $1 billion, one-fifth of the funding Trump asked lawmakers for, a request that left the nation on the edge of a government shutdown that could happen at the end of the year.

“I think it’s blowing up,” Kolfage told USA TODAY. “People like myself are frustrated, and they want something done. They’re passionate about it.”

Kolfage said he spoke to someone in the White House, though he declined to identify whom.

The White House is aware of the GoFundMe effort, but officials declined to comment on whether the administration coordinated with Kolfage on it.

There’s a hitch: Sending money to the government isn’t as simple as writing a check to the Department of Homeland Security and asking that it be used for border wall construction.

In fact, Homeland Security cannot even accept the money without the explicit approval of Congress. In its policy, the agency cites a federal law that states “gifts may not be accepted, used, or disposed of unless specifically permitted” by Congress.

“Before anything, Congress has to approve it,” said David Bier, a policy analyst at the libertarian-leaning CATO Institute. “It’s a small amount of money that’s not going to make much of a difference, but I would be surprised if Congress rejected it.”

In its policy issued in 2008, the DHS allows officials to “accept and utilize gifts to DHS that aid or facilitate DHS’s work,” if approved beforehand. Gifts with conditions attached – such as money specifically slated for a border wall –  have to be reviewed by the Office of the General Counsel.

Much of the policy is wrapped around ethical concerns and aims to halt outside money from swaying the agency’s decisions.

“Congress wants that control over what money is being used for and what agencies are doing, so you don’t have money coming in from unknown places influencing policy,” Bier noted.

The DHS did not immediately return a request for comment.

It’s not uncommon for private citizens to donate to their government. Under federal law, citizens, as “individuals wishing to express their patriotism,” are able to make donations to a general Treasury fund, “Gifts to the United States,” but those are general gifts to the government.

Over the years, millions have been donated in hopes of whittling down the national debt. Last year, more than $775,000 was donated to reduce the debt. In 2012, during the economic crisis, $7.7 million was donated.

Kolfage noted he hadn’t worked out how exactly the money would be delivered to the government and used for a border wall. He pointed to a $7.5 million private donation that was used to repair damage to the Washington Monument, which is operated by the National Park Service.

The Wall – An in-depth examination of Donald Trump’s border wall

In that case, the money was funneled through the Trust for the National Mall, a nonprofit partner of the Park Service.

Kolfage said in his crowdfunding campaign that he worked with Rep. Steven Palazzo, R-Miss., on legislation that would direct the Treasury Department to turn the money into savings bonds, which would allow the donations to be used for the border wall.

The bill, dubbed the “Border Bonds for America Act of 2018,” would allow Americans to purchase revenue bonds to help finance the construction of a southern border wall. It asks the treasury secretary to issue government savings bonds, known as “Border Bonds,” specifically for the construction of the wall.

Palazzo compared his bill to war bonds used to support the military during World War II.

“This legislation would allow for the patriots of today’s era to help support American security in the same way as previous generations,” Palazzo said. “The American people are fed up with the political games fueled by the Democrats’ inaction to secure our borders and protect our citizens.”

Kolfage noted the bill was “just one option,” and “there are others on the table being discussed.”

This year, Rep. Diane Black, R-Tenn., introduced a bill that would create a trust fund within the Treasury Department that would “accept public donations to fund the construction of a barrier on the border between the United States and Mexico.” Black’s office did not immediately return a request for comment.

“Whether it’s done with bills or whatever, they can make it happen,” Kolfage said.