What a 50-50 Senate Means, for Biden and for the U.S.

Full Democratic control of the levers of federal lawmaking under President Joe Biden rests on the slimmest-possible advantage in the U.S. Senate, where any party-line vote will result in a 50-50 tie. The even Senate split, rare in American history, gives the Biden administration little margin for error and is subject to a power-sharing agreement between the Democratic and Republican leaders.

The party of the vice president, who acts as president of the Senate and breaks ties when they occur. That’s the Democratic Party now that Kamala Harris is vice president. Her tie-breaking vote is what made the top Senate Democrat, Chuck Schumer, majority leader. (The Senate technically has 48 Democrats and two independents, Bernie Sanders of Vermont and Angus King of Maine, who reliably vote with them.)