The broad executive action on immigration that President Obama announced on Thursday night could shield nearly half of the estimated 11 million undocumented immigrants now believed to be in the U.S. from deportation.

But the move is much bigger than that.

The president is also directing the government to fundamentally reshape its priorities for enforcing immigration laws by focusing more intensely on removing criminals rather than families, overhauling immigration courts, and making changes to the high-skilled visa system.

Under the plan, the bulk of the estimated 5 million people who could be protected from deportation would be parents of U.S. citizens or green card holders who have lived in the country for more than five years. According to an analysis by the Migration Policy Institute, as many as 3.7 million undocumented immigrants could fall into this category; beginning next spring, they could register with the government, undergo a background check, start paying taxes, and gain protected status for up to three years.

Another 290,000 immigrants who were brought to the U.S. illegally as children would also be newly protected under an expansion of Obama's original Deferred Action for Childhood Arrivals (DACA) program. The administration is eliminating the age cutoff for DACA, which had been open only to people under 31, and it is allowing immigrants to apply if they have lived in the U.S. since 2010, not 2007 as before. The changes will increase the number of people eligible for that program to about 1.5 million, according to MPI. The White House says another 1 million immigrants would be newly protected from deportation under the other reforms in the president's directive. The policy institute estimates that the total number of undocumented immigrants now in the U.S. is 11.4 million people.