A group of Republican senators on Thursday unveiled its answer to President Trump’s border wall: a $15 billion venture to step up multifaceted border security without choking off trade.

The legislation, fronted by the chamber’s No. 2 Republican, Sen. John Cornyn of Texas, comes as a rebuke to the president for his singular focus on getting a border wall built and getting Mexico to pay for it — an endeavor Trump himself dismissed as the “least important” matter that he and Mexican President Enrique Peña Nieto would discuss in a January phone call, but “politically this might be the most important.”

It also comes as a rejection of the House GOP leaders, who recently pledged to fully fund Trump’s wall, approving the first $1.6 billion installment on it as part of the House’s recently passed defense authorization bill.

“Border security is not a one-size-fits-all proposition; we need an approach that will work at each unique place along the U.S.-Mexico border,” Cornyn told reporters Thursday.

The senators behind the legislation framed it as a chance to “regain the public’s confidence” and restore the public “trust deficit” in Congress after several rocky legislative months — not to mention years upon years’ worth of failed attempts to pass an immigration bill encompassing border security measures.

The legislation also gives Republican lawmakers an immigration platform to latch onto that has enjoyed widespread support in the past, just a day after many party members were openly criticizing a proposal from Sens. Tom Cotton (R-Ark.) and David Perdue (R-Ga.) to severely reduce legal immigration that Trump endorsed.

Cornyn congratulated Cotton and Perdue on Thursday “for initiating the debate again” on legal immigration, but was firm and clear that their bill was “a beginning, not the end.”

When Cornyn unveiled the bill Thursday, he was joined by Republican Sens. John Barrasso (Wyo.), Ron Johnson (Wis.) and Thom Tillis (N.C.). Their proposal authorizes $15 billion over four years to pay for border security infrastructure that includes a potential wall system, fences, levees, border surveillance technology — which the George W. Bush administration coined a “virtual wall” — and an increase in Border Patrol agents, Immigration and Customs Enforcement officers, and immigration court prosecutors and judges. Those judges would also be required to hear cases of unaccompanied minors who cross the border in an expedited fashion.

Cornyn declined to entirely rule out the president procuring money from Mexico to foot the bill, though he remarked that “we are used to Congress appropriating the money.”

The bill also incorporates legislation to end the “catch and release” of people who violate immigration law and to punish “sanctuary cities” that refuse to turn over undocumented immigrants to federal authorities by withholding federal funds.

Finally, Cornyn’s bill envisions more resources for border crossings and other ports of entry to make them “more efficient” and ensure that “trade can continue to flourish.” Cornyn has stepped out in recent months to counter Trump’s pledge to either get rid of or entirely renegotiate the North American Free Trade Act, or NAFTA, trumpeting the pact’s benefits for Texas.

Most of the measures in Cornyn’s bill have passed Senate muster before, as part of a comprehensive bill that the body approved in 2013. That bill was the result of intense bipartisan negotiations, and it matched the enforcement measures with initiatives like a pathway to citizenship for certain immigrants living in the United States without official status.

But those olive branches to immigrants — considered key to bringing Democratic support on board — are not part of Cornyn’s most recent proposal.