President Biden has been ever a willow, never an oak, bending under progressive winds. Now, however, congressional Democrats should consider tempering their enthusiasm with lucidity. That is, their enthusiasm about their many expensive enthusiasms, with lucidity about the electorate.

This is likely their only way to avoid a dispiriting, for them, 2022: Losing control of either congressional chamber would extinguish Biden’s legislative agenda. So, as the Democrats’ kamikaze caucus contemplates a (properly scored) $4 trillion-plus Build Back Better gusher to punctuate a year that has seen the highest inflation in 31 years, this caucus should ponder some data:

Biden’s agenda for swollen government resembles Franklin D. Roosevelt’s in 1933 and Lyndon B. Johnson’s in 1965. The stark differences are the popular-vote margins that put the three into the presidency: FDR, 17 percentage points; LBJ, 23 points; Biden, 4.5 points. So, in 1933, there were 59 Democratic senators (out of 96) and 313 Democratic representatives. In 1965, there were 68 Democratic senators and 295 Democratic representatives. Today, the numbers are 50 and 221. Analyst Charlie Cook says of 2020:

“The presidential race came down to 125,084 votes spread across Georgia, Arizona, Wisconsin, and Pennsylvania. A flip of just 62,543 votes and Donald Trump would now be [well] into a second term. In the Senate, the Georgia seat that put Democrats over the top was a matter of Jon Ossoff winning just 59,944 more votes than David Perdue. The margin in the House was 31,751 votes across five districts.”

In 2020, five states — Georgia, North Carolina, Arizona, Wisconsin, Pennsylvania — were won by margins of 1.5 percentage points or less. Biden won all but North Carolina. If Trump had won the three that Biden carried by less than 1 point — Georgia, Wisconsin, Arizona — he would be president.

The 2012 presidential election was the most recent one in which the Democratic candidate carried even 40 percent of Whites without college educations. Today, according to David Shor, a Democratic consultant, “If you look inside the Democratic Party, there are three times more moderate or conservative nonwhite people than very liberal white people, but very liberal white people are infinitely more represented” (emphasis added). And between 2016 and 2020, Trump increased his success with non-White working-class voters. Biden won a smaller share of both the White and non-White working class vote than Barack Obama received in 2012.

This is one reason Trump is the first incumbent president to increase his vote total — he did by 10 million — while failing to win reelection. Another reason is that just 10 percent of those who voted for Obama in 2012 and Trump in 2016 voted for Biden in 2020.

Ticket-splitting has declined: In 2020, only 16 of 435 congressional districts were won by a presidential candidate of one party and a House candidate of the other. In 2008, about 71 percent of Senate elections were won by the party whose presidential candidate carried the state. In 2020, the figure was 95.6 percent, the same as with House districts. But the three states Biden carried by the largest margins (Maryland, 33.2 points; Massachusetts, 33.5; Vermont, 35.4) have Republican governors.

In the 2021-2022 post-census redrawing of congressional districts, Republicans control legislatures in states with 187 districts, and Democrats have complete control in states with just 75. Furthermore, House races are susceptible to national waves, and since World War II, average midterm House losses for the president’s party are slightly worse in presidents’ first terms (23) than on average (22).

So, Biden could become the fifth consecutive president to see his party lose control of both the House and the Senate during his tenure. He could even lose both in the first midterm elections of his tenure. This most recently happened not recently — in 1994 and 1954, during Bill Clinton’s and Dwight D. Eisenhower’s first terms, respectively.

Today’s polarization is not unprecedented. When a 1936 Gallup poll asked, “Do you believe the acts and policies of the Roosevelt Administration may lead to a dictatorship?” 9 percent of Democrats said yes, 83 percent of Republicans said yes. Today, however, there is broad agreement among Americans about something: Last week’s Post-ABC News poll revealed that a landslide 59 percent are concerned that Biden would “do too much to increase the size and role of government.”

Now, about that Build Back Better gusher …