ONE OF THE TOUCHIEST topics in any election year is taxes - especially when what you're talking about is an increase in the tax burden on particular individuals. A case in point is the reaction of Mayor Walter Washington, city council chairman Sterling Tucker and council member Marion Barry to a recent proposal by the D.C. Tax Revision Commission. Under this proposal, organizations in the city that are exempt from paying property taxes would instead pay the city a fee of 10 per cent of the amount they would be billed if taxes were assessed. This recommendation, one of many that the commission submitted to the city council after a year of study and deliberation, would apply to churches, hospitals, schools and numerous nonprofit groups around town.

Now this is a rather sweeping proposal, well worth careful and comprehensive study. But the reaction of the city's political leaders centered almost exclusively on the proposal's implications for churches, conveniently ignoring all the other private institutions that have profit-making real-estate properties but do not pay property taxes on them. And their reaction also ignored a host of private organizations that are tax-exempt, including George Washington University and Hospital (valued at $147,141,147), Georgetown University and Hospital (valued at $122,241,290), National Geographic Society ($23,694,211) and Dumbarton Oaks ($8,872,946). More than 30 other properties, including the National Academy of Sciences, the Brookings Institution and the National Society of Daughters of the American Revolution, have congressionally mandated tax exemptions. And then there are the churches - whose real-estate holdings have a total market value of more than $404 million.

Why, then, preoccupation of the politicians with the churches? We cannot escape the conclusion that it may have something to do with the particular political sensitivity of the churches - and with the approach of an election year. Without being too cynical about it, it does seem that this might somehow account for Mr. Tucker's strongly voiced opposition to taxing churches, the mayor's promise to veto any such measure, and Mr. Barry's opposition to even holding hearings on tithing selected tax-exempt organizations of any kind.

Perhaps that's sound politics. A case could even be made, we suppose, that it is sound fiscal policy, as well. We are not prepared to conclude that the commission's proposals represent the best possible approach to the District's highly complex tax problems. But we do know that, for the sake of future solvency, these problems should not be left unresolved indefinitely. If they city's political leaders are not even prepared to consider one of the commission's most important proposals, the public will be at least entitled to ask each of them next year exactly how they would go about meeting the city's urgent revenue needs.