WASHINGTON — The federal government’s rescue of two failed banks last month has drawn criticism from some lawmakers and investors, who accuse the Biden administration and the Federal Reserve of bailing out wealthy customers in California and New York and sticking bank customers in Middle America with the bill.

But new data help explain why government officials declared the failures of Silicon Valley Bank and Signature Bank to be a risk to not just their customers, but also the entire financial system. The numbers suggest that a run on deposits at those two banks could have set off a cascading series of bank failures, crippling small businesses and economic activity across wide parts of the country.

The analysis of geographic risks from a banking crisis, prepared at the request of The New York Times, was done by economists at Stanford University, the University of Southern California, Columbia University and Northwestern University.

The results show the continuing potential for widespread damage to the entire banking system, which has seen many banks’ financial positions deteriorate as the Fed has raised interest rates to tame inflation. Those rate increases have reduced the value of some government bonds that many banks hold in their portfolios.

Although the damage has so far been contained, the research shows that larger runs on banks vulnerable to rate increases could result in a significant drop in credit available to store owners, home borrowers and more. Because so many counties rely on a relatively small number of financial institutions for deposits and loans, and because so many small businesses keep their money close to home, even a modest run on vulnerable banks could effectively stifle access to credit for entire communities.

That sort of credit paralysis, the researchers estimate, could afflict nearly half the counties in Missouri, Tennessee and Mississippi — and every county in Vermont, Maine and Hawaii.

The analysis helps buttress the case that government officials were making based on anecdotes and preliminary data they had when they orchestrated the bank rescues during that weekend in March. As fears of a wider financial crisis mounted, the Fed, the Treasury Department and the Federal Deposit Insurance Corporation acted together to ensure depositors could have access to all their money after the banks collapsed — even if their accounts exceeded the $250,000 limit on federally insured deposits. Fed officials also announced they would offer attractive loans to banks that needed help covering depositors’ demands.

The moves allowed big companies — like Roku — that kept all their money with Silicon Valley Bank to be fully protected despite the bank’s collapse. That has prompted criticism from lawmakers and analysts who said the government was effectively encouraging risky behavior by bank managers and depositors alike.