Fiona Ma isn’t promising to do for the State Treasurer’s Office what she helped do for her current post. That would mean all but eliminating it.

Since joining the Board of Equalization, Ma has seen the dysfunctional state tax panel reduced to a shadow of itself. And she says she would support a constitutional change to abolish it altogether.

In backing the reforms that brought the board to the brink of oblivion, the 52-year-old San Francisco Democrat showed a sense of responsibility to taxpayers that would suit the job she’s seeking. Along with her background in finance and politics, it makes her the best candidate to succeed State Treasurer John Chiang, who is running for governor.

A certified public accountant with master’s degrees in taxation and business administration, Ma worked for then-state Sen. John Burton before being elected to San Francisco’s Board of Supervisors. She went on to serve three terms in the state Assembly, where she championed legislation to ban potentially toxic chemicals from children’s products.

Elected to the Board of Equalization in 2014, Ma joined State Controller Betty Yee, an ex-officio member, in questioning the board’s mismanagement of funds and staff. She called for audits and ultimately Gov. Jerry Brown’s intervention, which led to legislation that shifted most of the board’s powers and staff to the governor.

Ma seems equipped to take more principled stands if, for example, California’s next governor lacks Brown’s penchant for fiscal responsibility.

Her most active opponent, fellow Democrat Vivek Viswanathan of Palo Alto, is one of the more intriguing newcomers in California politics. The 31-year-old former adviser to Brown and Hillary Clinton’s 2016 presidential campaign has been literally running through the Central Valley, logging as many as 34 miles a day, to get in touch with Californians. He has degrees from Harvard and Stanford and an impressive command of policy.

Viswanathan approaches issues most politicians would prefer to avoid — unfunded pensions and retiree health care, the inequities of Proposition 13, tax reform — with courage and specificity. But he lacks the elected experience he would likely need to be effective in a statewide office. With seasoning, he may have a bright future in politics.

Ma already has that experience as well as the knowledge and temperament to speak up for fiscal responsibility, which is why she’s The Chronicle’s choice for state treasurer.