By standing in the way of an auto industry bailout, GOP senators appear to have bitten the hand that fed them.
Over the last decade, General Motors has given $1.50 to Republican candidates for every $1 it has given to Democrats. That same pattern has been followed by Chrysler and Ford, which year after year have favored the right side of the aisle, sometimes by more than a 3-to-1 ratio in dollar terms.
Since 1990, the auto industry as a whole -- including suppliers, dealers and manufacturers -- has cut $100 million in checks to Republicans, compared with just $34 million to Democrats.
On Thursday night, the carmakers discovered just how little loyalty that investment strategy had bought them.
Efforts to get through even a watered-down version of the $14-billion aid package were stymied by Republican senators, many of whom contend that GM and Chrysler -- the most troubled U.S. automakers -- should simply go bankrupt.
"Carmakers have always leaned Republican," said Larry Sabato, director of the University of Virginia's Center for Politics. "But it'll be interesting to see whether what happened this week changes that pattern."
Political giving from the auto industry as a whole -- including carmakers, dealers and suppliers -- has long backed candidates that favor less regulation, lower taxes and looser labor rules, among other key issues.
This year, for the first time on record, Detroit's spending slightly favored Democrats. But since 2000, overall spending by the Big Three has steered 61% of contributions, or $7.2 million, to Republicans, according to Federal Election Commission data compiled by the Center for Responsible Politics.
Democrats, meanwhile, have looked to the United Auto Workers for support. Since 2000, the union has given $12.5 million to Democrats compared with only $94,540 to Republicans.
GM, the only carmaker that could be reached for comment, downplayed the role that money may have played in the current debate.
"It's highly doubtful that political giving ever played a factor in an individual member's position," GM spokesman Greg Martin said.
But on Capitol Hill, the cold calculus of money is never too far from any issue.
A study released Thursday by the Center for Responsive Politics suggested that in the House of Representatives, where the bailout passed this week, there was a direct correlation between votes and campaign cash: Those who voted in favor of the plan received, on average, 8% more money from the auto industry than those who did not.
In the Senate, other forces may have been at play.
Some of the loudest opponents to helping Detroit were senators whose states are home to car factories of foreign brands, including Sen. Richard C. Shelby (D-Ala.), who has Mercedes, Hyundai and Honda plants in his state but no Big Three facilities.
At the eleventh hour, Sen. Bob Corker (R-Tenn.) put forth a bill that sought to wrest new concessions from the United Auto Workers as well as from corporate bondholders. He has received $234,860 from the auto industry throughout his career, but Tennessee is also home to several Nissan plants and the Japanese automaker's U.S. headquarters.
"A part of this is certainly the old adage 'Where you stand is where you sit,' " said Norm Ornstein, resident scholar at the American Enterprise Institute for Public Policy Research.
Representatives of the two senators could not be reached for comment.
Labor was another issue underlying the tense negotiations. An action alert circulated among Senate Republicans on Wednesday called for Republicans to "stand firm and take their first shot against organized labor."
In doing so, analysts said, Republicans were planting the seeds for a fundraising appeal to big business -- other than the Big Three, of course -- as they gear up for a major political fight next year over expected legislation that would make it easier for unions to organize.
"They may lose money from the auto industry, but a union fight will get them a lot of money from the rest of the business community," Sabato said.
A final issue was ideological, experts say. For many conservatives in Congress, the idea of government rescuing any industry is simply unpalatable -- and that trumps any contributions from Detroit.
"The tension for Republicans is that it's an industry that's been staunchly in their camp for many years, but this is legislation calling for billions of dollars of government spending," said Massie Ritsch, spokesman for the Center for Responsive Politics. "It's a conflict between their principles and their longtime supporters."