The illegal immigrants who flooded the country under President Biden were a losing proposition for states and localities, which paid out nearly twice as much in increased costs for school and public safety as the migrants paid in taxes.

The Congressional Budget Office delivered the findings in an intriguing report this week that challenges longstanding conventional wisdom that immigrants usually more than pay their own way.

CBO said the surge, which began in 2021, added 4.3 million people to the U.S. population by 2023.

They paid slightly more than $10 billion in taxes to state and local governments in 2023. But those same governments spent $19.3 billion on goods and services for them — most of that in the form of schools for their children, housing and additional security.

Adding in other less tangible factors such as higher property tax collections from new housing, more crowding in classrooms and overburdened transit systems, CBO said the immigrants raised state and local revenue by $18.8 billion, but cost $28.6 billion — or a nearly $10 billion drain.

CBO said most studies of the impact of immigration look at all immigrants, both legally and illegally present.

In a report last year, CBO looked at the Biden immigration surge’s effect on the federal budget and found it was worth an additional $1.2 trillion in revenue over a decade compared with $300 billion in new spending on benefits.

The economy benefited from the legal/illegal surge, increasing the country’s gross domestic product.

But the average worker would be worse off at first because of the competition for jobs, CBO said. While the overall economic pie is bigger, it’s sliced into even more pieces.

Over time, those effects dissipate, CBO said, as the new arrivals spur higher productivity and economic demand.

• Stephen Dinan can be reached at sdinan@washingtontimes.com.