Biden and Democrats might be hoping that Tuesday night's State of the Union address will give him a political boost, but history shows that's unlikely to be the case.

When we compare Gallup polls taken just before State of the Union addresses since 1978 to Gallup polls taken just after them, we see that the president's approval rating typically doesn't move very much.

On average, a president's approval rating shifts by just 2.6 points after State of the Union addresses. But that shift is just as likely to be negative as it is positive. As a result, the average president has gotten just 0.4 points more popular after the State of the Union.

While a few presidents, such as Bill Clinton in 1998, have emerged from the speech in a significantly improved position, they are the exception, not the rule. And those changes may not even be attributable to the State of the Union; for example, then-President Donald Trump's approval rating rose 6 points after his 2019 address -- but the 2018-19 government shutdown came to an end just a few days before his speech.

-FiveThirtyEight's Nathaniel Rakich

Members of the Congressional Black Caucus and other Democrats will wear black pins tonight to highlight policing reform, an issue that has stalled on Capitol Hill but for which there have been renewed calls in the wake of Tyre Nichols' beating and death.

The round, black pins members are wearing have the year "1870" bolded in white. The year, they say, refers to the first known instance of an unjustified police officer killing of a Black person in the U.S, according to lawmakers.

Rep. Bonnie Watson Coleman, D-N.J., was passing out the pins along earlier with a card noting police killed Henry Truman in 1870.

"153 years later, nothing has changed," the card said.

Meanwhile, some Republican members have been wearing lapel pins resembling AR-15 rifles in recent weeks, distributed by Rep. Andrew Clyde, R-Ariz.

Biden is expected to address policing reform in his State of the Union address and has invited Nichols' parents to attend as his guests.

-ABC News' Senior Congressional Correspondent Rachel Scott

Biden will deliver his second State of the Union in a matter of hours, raising the question: What did he promise last year, and was he able to achieve what he laid out?

Among the top priorities he outlined last March were rallying American support for Ukraine in its effort to repel the Russian invasion and efforts to fight record-setting inflation. He said the State of the Union was strong "because you, the American people, are strong."

Yet, a new ABC News/Washington Post shows just 36% of Americans think Biden has accomplished a great deal or good amount as president; 62% say he's accomplished not very much or nothing at all.

And with Biden appearing poised to run for a second term -- and looking to use this year's speech to make his case -- nearly six in 10 Democratic-aligned adults don't want to see him nominated again -- and his approval rating after two years in office is well below average compared with the previous 13 presidents. Only one, former President Donald Trump, has lower numbers.

Click here are highlights of what Biden said last year and how things turned out.

Senate Minority Leader Mitch McConnell slammed Joe Biden for what he called the nation’s economic woes under two years of Democratic control -- just hours ahead of the president’s State of the Union address.

The Kentucky Republican appeared to rely heavily on new ABC News/Washington Post polling -- while not citing the data directly -- in remarks on the Senate floor, claiming Biden has created an America in which only 16% of citizens feel they are in a better financial situation than they were in two years ago.

"For 84 percent of Americans, one party Democratic control of Washington either failed to live up to its consequences or actively made life worse,” McConnell said.

McConnell hit Biden on inflation, immigration, the Afghanistan withdrawal, school choice, and more in the lead up to Biden's speech tonight.

He also criticized the administration for its handling of the Chinese spy balloon, arguing that it was "ludicrous to suggest that Canada and the United States had no choice but to let this thing traipse across the continent from coast to coast. "

–ABC News’ Allie Pecorin