The end of Title 42 has sent tremors across the U.S., marking a major shift in immigration policy at the U.S.-Mexico border.

The termination of the Trump-era public health order spurred a new surge at the already strained southern border, where a growing number of migrants from Central America continue to flee violence, poverty and economic and political instability with hopes of seeking refuge in the United States. President Joe Biden has warned of a “chaotic” period ahead, as the U.S. adjusts to a patchwork of policy solutions from the Biden administration, including a new rule that will bar most people from applying for asylum if they cross the border illegally or fail to first apply for safe harbor in another country.

Just how bad things could get — and for how long — is unknown. But the Biden administration is bracing for weeks of uncertainty: Border cities are struggling to manage the influx of migrants, troops have been deployed and political divisions over the country’s outdated, long-broken immigration system are bubbling up.