If present trends continue …

On a podium we shared the other day, my Republican colleague Whit Ayres summarized a great deal of what passes for political analysis. Preceding me in the speaking lineup, Ayres noted that in 2006 and 2008 he urged listeners in such forums to remember that it was a long time until Election Day and much could change. This year, he predicted, I would say the same thing — and he was partly right.

The relative place of continuity and change is an enduring question in all species of human knowledge.

There was a time when my children, waking up early for school, would ask what the weather would be that day. Without the benefit of a forecast, or even a peek out the window, I would reply from my bed, “Pretty much like yesterday.” Often I’d be close

Between Feb. 19 and 23 this year, the average daily temperature in Washington fluctuated between 39 and 40.7 degrees. Each day looked like the one before.

It’s a mental shortcut we all take — we assume tomorrow will look pretty much like today.

Hence we witnessed widespread Democratic triumphalism in the heady days after election 2008. In the joyous aftermath, one pundit proclaimed “the culmination of a Democratic realignment … Groups that had been disproportionately Republican have become disproportionately Democratic, and red states like Virginia have turned blue. Underlying these changes has been a shift in the nation’s ‘fundamentals’ — in the structure of society and industry, and in the way Americans think of their families, jobs and government. The country is no longer ‘America the conservative.’ … we may soon be ‘America the liberal.’ ” It sounds almost quaint today.

Some of the Democrats who decided then and there to run in 2010 no doubt predicted the future would look pretty much like the present — as did some of the Republicans who decided to retire.

They were just as likely to project the present into the future as those who were still writing about Republicans as a permanent House minority on the eve of 1994.

Indeed change — sometimes radical change — is ever-present. Looking up at a clear sky the morning of Feb. 3 and guessing the next day would be the same would have led you to miss the biggest snowfall in Washington’s history. The largest one-day net loss in the Dow Jones average was a poor predictor of movement the next day — a 485-point gain followed a 778-point decline.

Sometimes trends change dramatically without our even noticing. In 1960, 499 people were killed in airline accidents, which translated into 44.2 deaths per 100 million aircraft miles traveled. If the future had been just like the past, by 2007 (the most recent year for which data is available), almost 3,600 people would have died in airline accidents — that’s the equivalent of nine 747s dropping out of the sky each year, killing all aboard. It didn’t happen that way. Things changed. Air travel became a lot safer. Just one individual perished in an airline accident in 2007.

It is easy to put this down to technology. However, trends in human relations are not immune to dramatic change. For instance, since the Middle Ages, the murder rate in Europe has declined markedly. In the 14th century, there were about 32 murders per 100,000 inhabitants. By the 20th century, the murder rate was down to 1.4.

Assuming the future will look like the present is a natural tendency that often yields fairly accurate predictions. However, routinely betting on that assumption can lead to massive stock market losses, being ill-prepared for snow or feeling frightened when you can actually feel pretty safe.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982. Current clients include the majority leaders of both the House and Senate.