WASHINGTON, D.C. — One of President Donald J. Trump’s key campaign planks was his promise to build a wall on America’s southern border with Mexico. Although popular, estimates for the project have been costly, and Americans have debated how to pay for it ever since. On Tuesday’s edition of Tucker Carlson Tonight, Sen. Luther Strange (R-Ala.) discussed his new bill that provides a simple answer to that very question.

Instead of raising new taxes to pay for the wall, Strange wants to funnel taxpayer dollars away from sanctuary cities and towards the president’s project. “Our simple solution is that if you’re not going to comply with the law — we are a nation based on the rule of law — then we’re going to use that money to build the wall,” Strange told Carlson. “You just won’t get it.”

.@lutherstrange: #SanctuaryCities should foot the bill for border wall. #Tucker pic.twitter.com/jRuvU8SulK

— Fox News (@FoxNews) June 7, 2017

Strange’s bill is titled “The Securing the Border and Protecting Our Communities Act,” and it is cosponsored by Sen. David Perdue (R-Ga.). “They can either follow the law or fund the wall,” Strange said.

In addition to punishing sanctuary cities, the proposed legislation also seeks to help contractors located within them, which have been prevented from bidding for contracts on Trump’s wall project.

According to the Center for Immigration Studies, there are over 100 so-called sanctuary cities in the United States. The jurisdictions, which by their definition limit cooperation with state and federal authorities, are often in violation of federal immigration law.