Story highlights Lisa Gilbert: Marches are about signaling to Trump that the people do care about release of his taxes

They are also about standing up to a system that favors the wealthy over the working class, she says

Lisa Gilbert is Public Citizen's vice president of legislative affairs. Previously, Gilbert served as the deputy director and then director of Public Citizen's Congress Watch division. She advocates for government transparency and integrity, financial reform, civil justice and consumer protection. Public Citizen is a backer of the Tax March. The views expressed in this commentary are her own.

(CNN) Despite pledging he would release his taxes as soon as his "routine audit" was completed, right after his inauguration President Donald Trump flip flopped. When prodded, his counselor, Kellyanne Conway, glibly said that Trump had changed his tune because "the people don't care" about his taxes.

On April 15, many Americans will join Tax Marches in cities in almost every state to tell Trump that we do, in fact, care a great deal about his taxes.

Disclosure of Trump's returns is vital for understanding his conflicts of interest, but the Tax Marches are about more than just the need for an open, ethical and transparent government. They are also about Americans standing up against a rigged tax system in which billionaires pay a lower rate than secretaries, some profitable multinational corporations pay no federal income tax at all (due to corporate offshoring ) and small businesses and hardworking families are forced to pick up the tab to create the society we want to live in.

Though folks may grouse, most people in the United States take very seriously our collective responsibility to pay our taxes. We know that taxes help provide clean air and water, safe food and drugs, passable roads and bridges, protective police, successful schools and so many things that make our communities livable. We, therefore, need to create a more equitable system that closes loopholes, invests in communities and puts money in the hands of working Americans.

Trump's tax returns -- or lack thereof -- cannot be excluded from any discussion of a more equitable system. His returns are critical to understanding the true state of Trump's financial affairs. Without complete returns, we won't know whether he owes money to foreign governments or their leaders, how much he has given in charitable contributions, how much (if anything) he has personally paid in taxes and what some of his assets really are.