You know why Don Getty lost his seat, don't you? The Curse of the Crow. People don't like inflation, and they don't like politicians who patronize them with soft-money populist guff about ''high interest rates.'' With the new inflation numbers showing a strong upsurge, Getty's campaign against the Bank of Canada Governor proved his undoing.

Strangely, however, Crow will miss Getty. For as long as the whiners and recession doomsters are afield, the Governor's image as a hard-nosed inflation fighter is secure. As inflation mounts, it will be more difficult for him to sustain this illusion purely on the basis of a Rotary Club luncheon speech or two.

For illusion it most surely is. The canny Governor has combined tight-money rhetoric with loose-money practice: the broad-money aggregate M2 has been growing at a 15% annual rate over the past three months, and 13% over the past year. Curiously enough, this was also an election year, continuing the remarkable statistical correlation between federal elections and easier monetary policy.

It's clear what Crow has been trying to do: ''fool the workers.'' If he can convince wage-earners that, owing to his heartless monetary policy, prices are unlikely to rise more than the 4% or so we've become used to, they will be more likely to keep their wage demands accordingly moderate. If inflation is then twice what they were expecting, he can engineer a fall in real wages, and hence expand employment and output further.

WORKERS GETTING WISE

Until lately, it looked as though he might manage the trick. While inflation has been gradually accelerating through 1988, labor costs rose at a slower rate than in 1987 or 1986. But the evidence is that workers are starting to get wise. Some economists forecast wage rises at 6% before the year is out.

Meanwhile, in the U.S., a couple of months of frost-kill on the tomato crop and a drop in the unemployment rate is enough to convince a few of the usual hysterics that double-digit inflation is back.

But the liquidity just isn't there to support sharply higher inflation. The collapse in oil prices in 1986 wasn't enough to keep inflation down for more than a few months in the face of an inflationary monetary policy; nor can the current ''cost- push'' blip sustain itself against the sharp slowdown in M2 growth in the past nine months or so.

Monetary policy takes effect with long and unpredictable lags: the swell of U.S. inflation today is built on the rapid expansion of the money supply in 1985 and 1986, as the Federal Reserve obligingly co-operated in the Treasury's scheme to drive down the US$. Fed policy, in other words, has swung wildly, from loose to tight to just right to too tight again, all in just three years.

So: in the U.S., where policy is too tight, they're worried about inflation. In Canada, where policy is too loose, we're worried about recession.

The lesson of this continental state of confusion is that monetary policy does not operate in isolation. While the course of nominal output depends ultimately on the rate of increase in the money supply, how the economy adjusts in the meantime depends on the interaction between public policy and private actions.

If people do not understand that the Bank of Canada is inflating the economy, they may be fooled for a time. But once they become aware, they are unlikely to believe the Bank in future when it insists it is tightening. This was the lesson of the recession of the early 1980s: after 30 years of inflation, people could be forgiven for doubting the authorities' anti-inflationary resolve. It does not pay, in other words, to play with expectations.

Likewise, the structural flexibility of an economy determines how fast monetary expansion can be pushed without exciting higher inflation, and how much it can be slowed without tipping into recession. It may be that, at 5.1%, the U.S. has reached the level of unemployment where inflation begins to accelerate. But it may also be that the economic structure has been so limbered by eight years of deregulation that the natural rate of unemployment is even lower. No one knows.

All of these factors - lagged and unpredictable effects, shifting expectations, and political interference - make central bank attempts at ''fine-tuning'' worse than ineffective: they increase the dangers of recession. The best contribution the Bank of Canada can make to stabilizing the economy is to stabilize policy. It is more imperative now than ever that the Bank of Canada set a fixed rate of growth for the money supply, tell people what it is, and stick to it.