Senate Republicans blocked President Obama's "Buffett Rule," a measure that would impose a higher tax rate on the nation's wealthy residents.
The proposal failed in a 54-45 Monday. Democrats weren't able to secure the 60 votes required to keep debating the measure.
Under the Buffet Rule, America's top earners would pay at least 30 percent in taxes.
President Obama criticized Monday's vote, saying Republicans chose "once again to protect tax breaks for the wealthiest few Americans at the expense of the middle class."
"It's just plain wrong that millions of middle-class Americans pay a higher share of their income in taxes than some millionaires and billionaires," he charged.
But Sen. Jon Kyl, R-Ariz., said the measure was nothing more than Democrats' attempt to draw attention away from issues important to the public.
"This legislation will do nothing with regard to job creation, with regard to gas prices, with regard to economic recovery," he said.