When it comes to affordable housing - this year's hot political issue - Boston is like the famous line by the classic cartoon character Pogo: We have met the enemy and he is us.

First, a quibble about definitions. It used to be that affordable housing meant housing for those with low incomes. No more. When politicians talk about affordable housing these days, they really mean housing for middle-income folks - households making anywhere from  $50,000 to $75,000.

 Nevertheless, the now-redefined affordable housing issue is real enough. Think about this. In Boston, a modest, two-bedroom apartment costs a minimum of $190,000 to build. Meanwhile, a similar two-bedroom townhouse is available in nearby Salem for just $129,900. Or, if you like the Cape, you can pick up a six-bedroom, two-bath, close-to-the-beach house in Hyannis for $139,900.

 The differences in prices spell the difference between buying and not buying, renting or not renting. The median household income in Boston is $62,700. If one uses conventional household spending guidelines, a family making that much can't rent or buy in Boston. But in Salem or the Cape? No problem.

 The result? Middle-income families are leaving the city, seeking out cheaper properties elsewhere. Many of them, particularly renters, go unwillingly as rental rates rise beyond their means. Others, however, go happily. They are long-time homeowners who have suddenly discovered that the once-modest investment they made in a house is now worth a princely sum.

 In their stead arrive families with higher incomes who can afford Boston's significantly higher prices.

 The affordable housing issue has captured the attention of Boston's politicians - and for good reason.

 The city's housing stock is still largely rental dominated; about 60 percent of all residents rent. As rents rise, voters complain. In addition, policymakers fear that by driving out the middle-class, Boston becomes an unstable mix of the very rich and the very poor.

  The old-style housing activists in the Menino administration - the same people who desperately fought to preserve rent control in 1994 and who last year pretended to solve the housing crisis by imposing condo conversion controls - have this year pushed the notion of inclusionary zoning. Their new solution to the housing crisis is to require that 10 percent of all new residential units must be affordable.

 There's an absurdist quality to this proposal.

 If only 10 percent of new housing is to be affordable, isn't that an implicit acknowledgment that 90 percent of all new housing will now be unaffordable?

 Even worse, inclusionary zoning (like rent control and condo controls before it) is counterproductive.

 Its real effect will be to discourage housing development and boost housing costs. The 10 percent requirement simply means that developers have to subsidize the creation of some units. Some will say, ``Forget it,'' and build in places like Salem. Others will build in Boston, but will cover the extra expense by increasing the price of their other, non-subsidized units - in effect, increasing housing costs for 90 percent of all new residents.

 Rather than trying to impose new regulations, the question policymakers really need to ask themselves is this: Why is housing in Boston so scarce and so expensive? The answer, in large measure, is that it's the city's own fault.

The reason is straightforward: In a host of ways, Boston makes it too difficult and too costly to build or renovate.

For example, approvals for any projects are cumbersome and can easily consume years. City ordinances pile on rules and regulations. Zoning codes often discourage the creation of multifamily housing in, for example, local business districts. NIMBYism runs rampant. City councilors block projects unless there is virtually unanimous approval - itself a rarity. Construction codes discourage renovation of Boston's existing housing stock by boosting costs unnecessarily.

Often these issues simply mean housing won't be created. And even when it is, the delays and complexity that Boston imposes add significant costs to housing projects. How much? Developers believe the additional expenses are at least 15 percent.

Interestingly enough, if those costs could be eliminated, that $190,000 unit would then be around $160,000. If city government could make it easier and cheaper to build, the middle class could afford to live in Boston again.

 Tom Keane, formerly a Boston city councilor, writes regularly for the Herald. He can be reached at tomkeane@tomkeane.com