Watch live: President Biden delivers speech on the debt ceiling as U.S. default threat looms

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President Joe Biden will on Monday press lawmakers to raise or suspend the U.S. borrowing limit as the nation hurtles toward its first-ever default which would cause major economic turmoil.

Biden is expected to call on both Democrats and Republicans to put partisan bickering aside and address the debt ceiling before Oct. 18, when the Treasury Department estimates the U.S. will exhaust emergency efforts to honor its bond payments.

Economists can only guess at the ramification of what would be an unprecedented U.S. default, but many — including Treasury Secretary Janet Yellen and several predecessors — say it could be "catastrophic."

Yellen told House Speaker Nancy Pelosi, D-Calif., that diminished confidence in Washington's ability to make good on its IOUs on time would likely spark a jump in interest rates across the economy, tarnish the dollar's role as the globe's reserve currency and send shockwaves through financial markets.

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