These have been days that caused tongues to click, lips to purse, brows to furrow and fists to clench in both parties.

For at least one of the president's most trusted confidants, there were signs of trouble even before the Louisville debate. This confidant thought it was out of character -- undignified and unpresidential -- for Reagan to refer to his opponent as "whatshisname." Since Louisville, Republicans talk less about this being a "realigning" election. But they may be mistaken, at least in this sense: we may not be on the eve of a realigning election; we may be in the middle of a realigning era that no trivial event, such as a debate, can disrupt.

For Mondale, these have been the most satfyThe debate was the first moment since January tht his courtship of the electorate had not gone unrewarded. Until then, the more he campaigned, the more "negatives" became attached to him in polls. That pattern changed after the debate. But not much else changed. The "270 problem" -- electoral votes, that is -- is as intractable as before.

In the afterglow of Mondale's debate performance it was almost possible for Democrats to dream of President Mondale. Did I say dream? It may have been a nightmare for Gary Hart and Mario Cuomo. Hart would then have to run for reelection to the Senate in 1986. After you have been the lion of New Hampshire, the star of Super Tuesday and the toast of California, it is hell to go back and beg for votes in Pagosa Springs, Colo. And Cuomo would have to run for governor again. Albany has many charms, but . . .

(My hunch is that Cuomo will run again in any case. He will pledge to serve a full term, which is fine. But he will mean it. He, like me, has a picture of Thomas More on his wall. I, unlike Cuomo, have a flicker of sympathy for Henry VIII, who found More exasperatingly unyielding.)

But the odds against a Mondale administration remain high, for reasons that have little to do with Mondale personally, and much to do with his being a Democrat. That is an imprudent thing to be in a Republican presidential era, which Horace Busby says this is.

Busby, a Tory Democrat from Texas, who served in LBJ's White House, now is a Washington consultant who writes one of the town's most interesting newsletters, in part because his pocket calculator never sleeps. He reports that in 1980 some voter cast the billionth vote cast since 1856 for a presidential candidate of the Republican or Democratic parties (more than half the billion have been cast since 1952). In this, "the oldest continuous political competition in the world," the popular vote split has been amazingly even. During these 124 years, each party has received more than 500 million votes -- Republicans 51 percent, Democrats 49 percent.

But Republicans lead in elections won, 19 to 13. And 54 percent of the electoral votes have gone to Republicans, 46 percent to Democrats. There have been eras of lopsided dominance. From 1860 to 1928 Republicans won 61 percent of the electoral votes. From 1932 through 1948 Democrats had the strongest dominance yet recorded: 83 percent.

In the four elections beginning in 1968 Republicans have won 74 percent. The 1932-48 Democratic dominance was really FDR's one-man show: in 1948 Truman did not even get a majority of the popular vote. (Since 1944 no northern liberal Democratic candidate for president has received a majority of the popular vote. The only two Democrats who have -- LBJ in 1964 and Carter, barely, in 1976 -- were from states of the Confederacy.) If Reagan wins this year and a Republican wins in 1988, Republicans will govern at least until 1992, establishing a 40-year dominance under four elected presidents.

Since 1920, seven of the 15 elections have been landslides, with the winner getting more than 400 electoral votes, as in 1980. But in the elections immediately after four of those seven, the party that had won the landslide was defeated (1932, 1960, 1968, 1976). Therefore, Busby may see more inevitability than history will admit.

But in recent days a small event (the Louisville debate) has caused many people (including bored journalists hungry for a more stimulating story) to exaggerate the fluidity of American politics. So it is salutary to be reminded of the length and steadiness of the pendular movements in American politics. The electorate believes certain things, not capriciously, and the parties stand for certain things, not frivolously. These, not 90-minute episodes, govern politics. And they make the electorate move more like maple syrup than mercury.