Rowdy Republicans yell and taunt Biden during his State of the Union after McCarthy warned them to behave

• Republicans repeatedly heckled Biden during his SOTU address.
• It was an unorthodox display of behavior during what is generally a tame event.

Republicans repeatedly interrupted and heckled President Joe Biden during his State of the Union address on Tuesday night, offering a theatrical reminder of the historically contentious state of US politics as millions of Americans watched on live TV.

Biden's comments on a range of issues — everything from the national debt to fentanyl overdoses — prompted boos and loud yelling from Republicans. The president appeared to be largely unfazed by the GOP's unorthodox behavior, at times directly responding to their jeers.

GOP Rep. Marjorie Taylor Greene of Georgia, for example, shouted "liar" after Biden suggested that some in her party wanted to see Social Security and Medicare end. Biden ultimately got Republicans to stand up and applaud in support of both programs, and declared there was "unanimity" on the matter.

Greene, a particularly vocal attendee of Biden's address, at another point shouted "China spied on us" as the president discussed tensions between Washington and Beijing — including the recent downing of a suspected Chinese spy balloon.

The raucous behavior of a number of congressional Republicans came after House Speaker Kevin McCarthy insisted that members of his caucus behave during the address.

"We're members of Congress. We have a code of ethics of how we should portray ourselves," McCarthy said to CNN's Manu Raju on Tuesday. "And that's exactly what we'll do."

McCarthy, who said there would be no "childish games" during Biden's speech, was ultimately seen shushing Republicans who were yelling as the president addressed the nation.

The behavior of Republicans on Tuesday night was indicative of McCarthy's struggles to control his caucus after barely clawing his way to the speakership last month — a dramatic fight that saw him to make a number of concessions to hyper-conservative members.

It was also emblematic of the rising animosity between Democrats and Republicans under a newly divided government, at a time when far right elements of the GOP are becoming more and more influential — and increasingly steering the tone of the party.