Earlier this summer, the Supreme Court struck down a provision of the Voting Rights Act that set the preclearance formula used to determine which states and jurisdictions must receive federal approval before changing their voting laws. Texas was one of the nine states that used to require federal approval. 

President Obama criticized the Supreme Court decision, saying it would increase potential voter discrimination. Cornyn said Obama didn’t like the ruling because it wouldn’t politically favor Democrats — a party that counts on minority voters as a core bloc.

“Why are President Barack ObamaBarack ObamaTrump plays golf for third weekend in a row Former Defense chief: Trump's handling of national security 'dysfunctional' Priebus, Wallace clash over media coverage of Trump MORE and his Attorney General, Eric HolderEric H. HolderEllison needles Perez for 'unverifiable' claim of DNC support With party in trouble, Dems hit voting laws Bottom Line MORE, so upset about this decision? The answer is as simple as it is disturbing: partisan politics,” Cornyn wrote.

After the court decision, the Justice Department filed a federal lawsuit to reinstate preclearance over Texas using a different provision of the Voting Rights Act. 

Cornyn argued that the Justice Department is wrong to say Texas intentionally discriminates against minority voters and will lose the case because the rate of voter registration among Hispanics and African-Americans in the state has increased during the past 10 years.

“Unfortunately, these facts mean little to a politicized Justice Department bent on inserting itself into the sovereign affairs of Texas,” Cornyn said. “As Texans, we reject the notion that the federal government knows what’s best for us. We deserve the freedom to make our own laws and we deserve not to be insulted by a Justice Department committed to scoring cheap political points.”

Texas has implemented a voter ID law, which some Democrats say discriminates against the poor, elderly and minorities, who are less likely to have a government-issued photo ID. The law requires anyone voting to present a valid photo ID before casting a ballot.