About a year ago, President Trump pledged to eliminate the national debt "over a period of eight years." But for the first time in history, the national debt surpassed $21 trillion this week, according to the U.S. Treasury.

The landmark comes shortly after Congress passed, and Mr. Trump signed, a suspension on the federal debt limit last month, allowing the government to borrow an unlimited amount of money until March 1, 2019.

When Mr. Trump took office on Jan. 20, 2017, the national debt was $19.9 trillion, according to U.S. Treasury data. Since then, the GOP-led Congress has passed a $1.5 trillion tax cut bill and a two-year spending deal which, together, are expected to drive the deficit and debt further upward. The Committee for a Responsible Federal Budget estimates annual deficits could top $2.1 trillion per year in the next decade, which would send the national debt soaring even higher.

Republicans railed against the national debt level under the Obama administration, when it jumped from $10.6 trillion to $19.9 trillion, nearly doubling, but few have been as outspoken about the situation with Republicans controlling Capitol Hill and the White House. Sen. Rand Paul, R-Kentucky, held up the spending bill last month on the Senate floor, blistering Republicans for doing exactly what they had criticized the Obama administration for doing.

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"I ran for office because I was critical of President Obama's trillion-dollar deficits," Paul said at the time. "Now we have Republicans hand-in-hand with Democrats offering us trillion-dollar deficits."

Sen. Bob Corker, R-Tennessee, called the national debt the "greatest threat to our nation" when it exceeded $20 trillion for the first time in September.

Greatest threat to our nation is our inability to get our fiscal house in order. My statement on the national debt: https://t.co/1lfyQ2jH5z. https://t.co/IJB4JE9YGz — Senator Bob Corker (@SenBobCorker) September 12, 2017

But the ever-increasing national debt isn't a frequent topic for Mr. Trump, and when it does come up, he doesn't seem too concerned. He's said he's open to eliminating the debt ceiling entirely.