G.O.P.-Led States, Claiming ‘Invasion,’ Push to Expand Power to Curb Immigration

Republicans’ latest efforts capitalize on the issue’s prominence in the 2024 election. But the fate of their proposals is still being litigated.

Nearly a year since Texas adopted a law empowering state and local police officers to arrest undocumented migrants who cross into its territory, Republican lawmakers in at least 11 states have tried to adopt similar measures, capitalizing on the prominence of immigration in the 2024 presidential election.

The fate of the proposals — six have been enacted or are under consideration, with Louisiana expected to sign its measure into law as early as next week — is still being litigated. In a case before a federal appeals court, Texas is defending its law by arguing that illegal immigration is a form of invasion, allowing it to expand its power to protect its borders. Federal courts have previously ruled that, from a constitutional perspective, the definition of the term invasion is limited to military attacks.

States have tested the limits of their power over immigration before, but lawyers and legal scholars said the push this year was accompanied by what had amounted to a public-relations campaign.

In campaign speeches, political ads and the halls of Congress, more Republicans are echoing former President Donald J. Trump by arguing that the rise of migration at the southern border is an “invasion.” President Biden, under pressure from both Republicans and Democrats to tackle the issues at the border, signed an executive order this month to curb asylum, and he could have more actions coming next week.

The measure expected to be signed by Gov. Jeff Landry, Republican of Louisiana, includes provisions allowing Mr. Landry and his attorney general to establish a compact with Texas to address border security. Mr. Landry has already met with Gov. Greg Abbott, Republican of Texas, and dispatched Army National Guard soldiers from Louisiana to Texas’ border with Mexico.

Valarie Hodges, the state senator in Louisiana who wrote the legislation, joined other Republicans in calling Mr. Biden’s recent action “too little, too late,” saying in an interview that state measures like hers were essential because the Biden administration had failed to enforce immigration laws.