Former Rep. Ron Paul (R-Texas) said Tuesday that President Trump’s proposed wall along the southern border is not the best solution to curbing illegal immigration.

“I don’t like walls. I don’t want to wall people in and wall people out,” Paul said on CNBC’s “Squawk Box.”

“I don’t want free, open borders either,” he continued. “I think you have to remove the incentives for people to come.”

{mosads}Paul, who ran for president in 2008 and 2012, argued that welfare programs and an easy path to citizenship entice immigrants to come to the U.S. He suggested that removing those incentives would be a more effective deterrent to illegal immigration.

Paul’s comments come as the government enters the 18th day of a partial government shutdown that has been spurred by Trump’s demand for more than $5 billion in funding for a wall along the U.S.-Mexico border.

Democrats have offered $1.3 billion for border security measures but have refused to provide money for the wall.

Trump is set to deliver an address on Tuesday night and visit the southern border on Thursday as he continues to press his case for the wall.

Paul’s son, Sen. Rand Paul (R-Ky.), suggested last week that a compromise between the two sides that includes some type of funding for the wall could lead to an end to the shutdown, WKMS in Kentucky reported. Paul, who is an adamant fiscal conservative, has emerged as a key ally of the president’s in the Senate.