Like an addict who always wants one more fix, Boston can't seem to stem its craving for rent control.

Rent control ended back in 1994 after a statewide referendum. Following a two-year transition, Boston's enormously complex controls over rents, rentals and condos were seemingly abolished. Since then, however, the Mayor and the City Council have three times passed new laws to try to reestablish some form of rent control in Boston. Three times, those new laws have been challenged in court and, three times, the courts have rejected them.

Undeterred, the Mayor this week sent to the Council his fourth bite at the rent control apple. Judging by the enthusiastic response of Councilors who signed onto the proposed ordinance, this measure too will soon become law.

The new measure is billed as an effort to keep housing affordable. Admittedly, some of the protections the ordinance offers up, such as giving tenants a right of first refusal to buy their apartment if it's turned into a condo, make sense. But the real thrust of the ordinance is to prevent any rental apartments from being converted to condos. It does this by imposing a five-year ban — three years more than existing state law — on most condo conversions and requiring strict rent controls for anyone who seeks to convert their building into condos.

Few question the notion that Boston has a lack of affordable housing. The cost of housing in Boston is climbing — skyrocketing in some of the more desirable neighborhoods. Middle income families, those earning $40,000 to $50,000 annually, find it increasingly difficult to stay in the city. But the Mayor's new proposal will do little to solve this problem. Indeed, it will likely exacerbate it.

The affordability crisis is being driven by those familiar economic gods of supply and demand. Over the last several years, demand for housing has increased in Boston, driven by a strong economy and a newfound love of urban living. The nature of the demand has changed as well. New residents are frequently former suburbanites who, now empty-nesters, decide to retire to Boston instead of Florida.

Meanwhile, the supply of housing has so far increased slowly. Some of this is due to the inherently slow process of construction. Some also is the city's fault. Boston's snail-like and convoluted approval process adds months, if not years, to any new development or rehab.

Does the new ordinance fix any of this? Not at all. Indeed, its net effect will be to increase housing costs and decrease the supply of rental housing.

Over the last few years, the city has tried to make home ownership easier and more affordable for lower-income families. It has encouraged use of such things as soft-second mortgages, which reduce the need for a down payment on a house purchase. The effect of all this has been to increase demand for home ownership. Given Boston's low supply of single family homes, most of those newly bought homes are condos.

But the Mayor's new ordinance seeks to prevent any new condo conversions. On the one hand, the Administration is trying to encourage new home ownership. On the other, the new ordinance is trying to dampen the supply of new homes. The effect, of course, will be to drive the price of existing condos up — thereby exacerbating the affordable housing crisis.

More broadly, the new ordinance will scare off any new rental housing developments. Potential developers of new rental housing will be put off by the sharp restrictions on condo conversions. Those developers, and their lenders, want the flexibility to respond to future market conditions, including potentially converting rentals to condos. Robbed of that flexibility, rental developers will simply opt not to go forward, or perhaps, will simply build outside of the city.

Perverse effects like these are common when governments seek to intrude on markets. For the Mayor and the City Council, the opportunity of bragging to constituents that they fought for them against greedy landlords is an opportunity that just can't be passed up — even though it is those same constituents who are hurt in the end.