The plan, outlined in a public notice posted Thursday, is the latest step in an unprecedented Trump administration initiative to pool confidential data from varied sources that it claims will help identify noncitizens on voter rolls, tighten immigration enforcement and expose public benefit fraud.

According to emails obtained by ProPublica and The Texas Tribune, DHS approached Texas officials in June about a pilot program to add the state’s driver license data, but it’s not clear if the state participated.

Incorporating driver’s license information would allow election officials whose rolls don’t include voters’ Social Security numbers to conduct bulk searches by driver’s license number. Ultimately, the system would link these two crucial identifiers for the purpose of citizenship checks, said Michael Morse, a professor at the University of Pennsylvania.

“It is the key that unlocks everything,” Morse said.