The Postal Service announced earlier this month that it would get rid of Saturday delivery of first-class mail but would continue to deliver packages that day. Postmaster General Patrick Donahoe said the move would help save around $2 billion per year.

Minorities and young people were less supportive of the change.

Among nonwhites and those aged 18 to 29 years old, fewer than half support the plan to eliminate Saturday delivery. Only 58 percent of those with middle or lower incomes back the plan, while three quarters of those in the highest income brackets back the plan.

Republicans are significantly more supportive of the reforms, with 69 percent backing the elimination of Saturday delivery and 7 in 10 approving of the reduction in branch hours. By contrast, 56 percent of Democrats support eliminating Saturday delivery, and 63 percent back closing branch offices on weekends.

Some lawmakers are challenging the Postal Service's authority to unilaterally eliminate Saturday service. In a letter last week, Reps. Gerry ConnollyGerald (Gerry) Edward ConnollyOvernight Energy: Pruitt proposes rule targeting 'secret science' | Dems probe Pruitt's security chief | FAA bill provisions could strip endangered species protections Dems seek probe into Pruitt aide banned from banking Overnight Energy: Dems raise new questions about Pruitt's security | EPA rules burning wood is carbon neutral | Fourth GOP lawmaker calls for Pruitt's ouster | Court blocks delay to car efficiency fines MORE (D-Va.) and Sam GravesSamuel (Sam) Bruce GravesLawmakers left with more questions than answers on Trump infrastructure plan Five obstacles to Trump's infrastructure ambitions White House still eyeing gas tax hike to pay for infrastructure plan MORE (R-Mo.) pointed out that postal officials previously had requested congressional approval to make changes to delivery service.

“Logic dictates that when USPS and the administration repeatedly request that Congress explicitly provide USPS the authority to reduce mail service from 6-days to 5-days, it is clear acknowledgement that, absent Congressional action, USPS lacks the statutory authority to do so,” the pair wrote.