Senate Majority Leader Harry ReidHarry Mason ReidMcConnell not yet ready to change rules for Trump nominees The Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate Trump to press GOP on changing Senate rules MORE (D-Nev.) on Monday said $3 trillion of the U.S. budget deficit was caused by tax cuts to the rich under the Bush administration. 

Reid made the comment in floor remarks in which he welcomed President Obama's plan to raise taxes on the wealthy to help reduce the deficit.

"More than anyone else, these millionaires and billionaires benefited from Bush tax cuts and contributed $3 trillion to our deficit, to help plunge this nation into a financial hole," Reid said on the Senate floor. "A balanced approach to reduce our deficit means those who have benefited the most from policies that created our deficit should also help solve our deficit."

Reid added that the plan is a "concrete strategy" that "calls on those who have benefited from the tax policies that sunk this country deeper and deeper and deeper into debt to help get us out of this debt."

Obama on Monday sent up his detailed plan for reducing the deficit, which includes proposals to close tax loopholes and impose a "Buffett rule" that says people earning $1 million a year or more cannot pay a smaller percentage in taxes than average Americans. Reid said Americans "believe that many of the richest few should pay more, and one of the richest of all, Warren Buffett, agrees."

"Warren Buffett believes it's unfair that he pays a lower income tax than his secretary," the majority leader said.

Republicans continue to reject the idea that tax hikes are a way to address the deficit, given the detrimental impact on job creation they said these taxes would have.

In his opening remarks on Monday, Reid said the Senate would take up a bill offering 129 countries duty-free access to the U.S. market under a bill renewing the Generalized System of Preferences (GSP) program. But he also said the Senate must attach Trade Adjustment Assistance (TAA) legislation to that bill to help workers who have lost their jobs to international trade.

The Republican-controlled House has already passed a GSP bill without any TAA renewal. But Reid blamed Republicans for failing to embrace TAA, which he said is making it harder to move on three pending free-trade agreements with Colombia, Panama and South Korea.

"It's unfortunate that my Republican colleagues who say they care so much about free trade have prevented three such agreements from moving forward because of objections to this Trade Adjustment Assistance legislation," Reid said.

"As we struggle to rebound from the worst recession in generations, it's unthinkable that we would abandon hard-working Americans who lost their jobs through no fault of their own," he added. "The Trade Adjustment Assistance legislation provides the lifeline they need to get back on their feet."

Republicans have pushed for passage of the three trade deals first, in particular since the president himself has repeatedly stressed the need to finalize those agreements.