"The only time the NDP wins is when the free enterprise vote is fractured."

That's what one young BC Liberal delegate declared at last fall's annual party convention. It's the same powerful argument, not to mention a vain one, that the Liberals and Social Credit have been making for more than half a century -- and as it turns out, cautioning against such a split is a powerful weapon.

"The reason it's employed is because it is readily received as being true," says Martyn Brown, who has also served as a senior election campaign official with the Social Credit and B.C. Reform parties. "From both the left and the right. The NDP have equally made the argument: split the vote and you elect the other guys."

But besides missing the point on why people vote for third parties, the argument against splitting the free enterprise vote ignores the way voters behave by assuming there is one universe of NDP voters and another made up of anti-NDP voters, with no crossover.

One example? In every one of the seven elections that Social Credit leader W.A.C. Bennett won in B.C., the "free enterprise" vote was split. The Liberal party took 25 per cent of the popular vote in 1952 and it continued to take about 20 per cent of the vote for as long as Bennett won elections.

By 1972, Bennett's government was long past its best-before date, and on election day, the free enterpriser's nightmare came true. Vote splitting, it was said, defeated Social Credit and let the NDP swarm into power.

The Socred vote dropped 15 percentage points between 1969 and 1972. And the Liberal vote dropped, too, by about two-and-a-half points. So you can't accuse the Liberals of vote splitting. Must have been the Conservatives, whose vote jumped 11 percentage points.

But according to University of Victoria's Norman Ruff who ran the numbers from that election, even if every Conservative vote had gone to Bennett, the Socreds still would have lost. The result would have been much closer, but the NDP still would have pulled out a narrow majority government, Ruff says.

Between 1969 and 1972, the NDP vote jumped more than five points. Those votes had to come from somewhere. Maybe some former Socred voters did the unthinkable and -- not content to merely split the free enterprise coalition -- actually switched sides and voted socialist. Or maybe a lot of former Socred voters jumped to the Liberals at the same time that an even bigger tide of former Liberals was switching to the NDP.

Editor: Read the rest of Tom Barrett's in-depth Tyee feature today on the "myth of demon vote splitting" in B.C.'s political history by clicking here.

Tom Barrett is a Tyee contributing editor. Read his previous Tyee stories here.