Sen. Susan Collins, R-Maine, a co-sponsor last year of the legislation that would have required waiting at least two years to end Saturday mail delivery, received $70,500, more postal union donations than any Republican in Congress. Calls to Collins's office over two days weren't returned.
In the House, 197 out of 200 Democrats received postal union PAC donations, compared with 72 of the 232 Republicans.
California Rep. Darrell Issa, chairman of the House committee with oversight over the Postal Service, had the most donations among House Republicans, $44,500. Issa, who has said he backs ending Saturday mail delivery, said the union donations don't affect his position.
The biggest postal-union donor was the National Association of Letter Carriers, which trailed only the American Federation of Teachers among union political committees in campaign giving for the 2012 elections.
Democrats say they're concerned about the impact of postal service changes on employees. Maryland Rep. Elijah Cummings, the top Democrat on Issa's House Oversight and Government Reform Committee, said 45 percent of Postal Service employees are minorities, 40 percent are women and 21 percent are veterans. Some might not be able to find other work if they lose their jobs, he said.
"Our main concern is compassion for those who have given their blood, sweat and tears to make our mail system work," Cummings said.
Union officials including Fredric Rolando, president of the National Association of Letter Carriers, say most proposed cuts aren't necessary because the Postal Service's financial woes stem from its legal requirement to prepay costs of future retirees' health benefits. The service has defaulted on those payments for the past two years, $11.1 billion in all, and last week said it won't be able to afford this year's payment.
Rolando said his union contributes to candidates regardless from both parties who support the Postal Service.