Unless they are used as strictly temporary measures, rent-control ordinances (municipal regulations placing limits on rent increases) have several negative effects for renters.
Premise
Unless rent controls are strictly temporary, they have several negative effects, including bringing about a shortage of rental units (a long-term effect).
Premise
The advantage of rent control (smaller rent increases) is immediate; the shortage is long-term.
Premise
In municipalities where renters have a secure hold on political power and can enact or repeal rent control, those renters are invariably guided by short-term gain.
Anticipate
Combining: in those tenant-controlled municipalities, the short-term mindset means rent control will be enacted (or kept) for the immediate benefit, regardless of long-term cost. So those municipalities will have rent control for non-temporary periods, which means they'll experience the long-term shortage. Therefore, in many municipalities, there will be a shortage now or eventually.
Goal
Find an answer establishing that many municipalities will face a rental shortage.