When conservationists talk about “saving” this and “protecting” that, a logical question might be: Saving it from whom? Protecting it from whom? And why should the government force what you want on someone else who obviously wants something different, or there would not be an issue in the first place?

After all, the Constitution says that all citizens are entitled to the “equal protection of the laws.”

Such questions almost never get asked. Nor do evidence or logic play much of a role in most conservation issues. Instead, we hear rhapsodies about “open space,” sneers at “urban sprawl” and self-congratulatory phrases like “smart growth.”

In short, rhetoric has long since replaced reasons on this as on so many other issues.

The latest conservation crusade has been announced in the San Francisco Bay area — putting an additional one million acres aside as “open space.”

According to an official of the Peninsula Open Space Trust, the next couple of decades represent “the last chance” to “save” these million acres. The fashionable phrase is: “Once it’s paved, it can’t be saved.”

Just to introduce a few facts into all these rhetorical flourishes, there are four and a half million acres of land in the San Francisco Bay Area. Less than one-sixth of this land has been developed. So we are not talking saving the last few patches of greenery from being paved over.

More than a million acres are already legally off-limits to development while less than three-quarters of a million acres are actually developed.

What then is the urgency about making another million acres of land legally off-limits to building anything? Because otherwise, more people will move into the area over time and, since they don’t want to live outdoors, they will want to have housing.

That bothers the conservationists, who prefer trees to houses.

If they can’t cut these other people off at the pass by making it illegal to build anything on an additional million acres, they can at least force those people to live in the kinds of housing that conservationists want to restrict them to, rather than the kinds of housing that these people prefer for themselves.

That’s called “smart growth.” What is smart about it is another question.

An international study of 26 urban areas with “severely unaffordable” housing found 23 of those 26 subject to strong “smart growth” policies. What is “smart” about causing skyrocketing housing prices by making it illegal to build anything on vast amounts of land?

It is smart if you already own a home and the astronomical costs of buying or renting are going to have to be paid by other people who move into the area. It may be especially smart if restrictions on building cause the value of the home you already own to go up by leaps and bounds.

The San Francisco Bay area already has housing prices about three times the national average. The heavy burden that this places on people is reflected in the fact that two-thirds of the purchases of homes last year were financed with risky “interest-only” loans.

That means that the mortgage payments for the first few years do not reduce the amount owed by one cent. Moreover, since these are usually adjustable-rate mortgages, the payments can shoot up as the Federal Reserve raises interest rates.

The connection between severe restrictions on building and skyrocketing housing prices can be seen from evidence around the country and around the world, wherever people have succumbed to rhetoric about “smart growth” and sneers at “urban sprawl.”

Severe restrictions on building began in the Bay Area back in the 1970s. At the beginning of that decade, housing in this area was as affordable as in other parts of the country.

A median income family in the Bay Area could pay off the mortgage on a median-priced house in just 13 years, using just one-fourth of their income. A decade later, it took 40 percent of their income to pay off the mortgage in 30 years. Today it requires 50 percent. Very “smart.”