I’ve spent my whole career engaged in progressive organizing for social justice, both inside City Hall and out on the streets.

For 25 years, I’ve been fighting for affordable housing and stronger tenant protections. I’ve been arrested for civil disobedience in support of striking immigrant carwasheros, and was there for the very first Fight-for-$15 action in Downtown Brooklyn.

My proudest win in the City Council was my work (with Jumaane Williams) to rein in discriminatory stop-and-frisk policies, by banning bias-based profiling and creating an NYPD inspector general. I’ve passed laws to strengthen our campaign finance system and reform the Council’s rules, and helped bring participatory budgeting to NYC.

And I’m eager to see us go much further — in confronting inequality, dismantling segregation, divesting from fossil fuels, closing Rikers Island and reforming the criminal justice system, expanding citizenship, and yes, democratizing ownership and wealth.

Most of that work has been done in coalition with the Working Families Party, progressive labor, and grassroots organizations. I’m proud to be a founder of Local Progress, and a strong believer in building “movement progressive” infrastructure that helps us make durable change over the long term.

So I have immense respect for the campaign Bernie Sanders has run, and the passion his supporters feel (including many of my friends and neighbors, headed up to Brooklyn’s Prospect Park today for his rally).

You have helped make this election about income inequality, the cost of college, the need to rein in Wall Street, and the urgency of climate change. For the past months, he has been the lead campaign organizer for these critical causes.

But now, it’s time to elect a President — not a lead campaign organizer.

To me, that choice is pretty clear: I will be voting for Hillary Clinton.

Because I share so many goals and values with Sanders supporters, it seemed worth explaining why I’m supporting Hillary.

First, we need a candidate who will win the general election. There is just too much at stake, with Donald Trump and Ted Cruz lurking. I’ve seen the polls that say Bernie would beat them — but I think any honest person has to worry. We might not like it, but all the evidence says that we’ll need more centrist votes to win (especially in the absence of historically high African-American and Latino turnout).

In a parliamentary system, I would be a member of the Working Families Party, knowing we could build a coalition with Democrats to govern. But in the majoritarian system we have, well, we have to build an electoral majority.

And there’s just not — yet — a majority of voters for democratic socialism.

Second, we need a President who can advance the ball on concrete goals. Bernie is certainly more visionary in how he exhorts us to action. But the job of the President is to get things done, step-by-step. You want a real shot at getting a liberal Supreme Court justice confirmed by the Senate, to protect women’s reproductive health or workers’ rights to organize? Or how about actually raising the federal minimum wage, paid family leave, protecting the Paris accords and accelerating clean energy? Or attracting the best people to run the federal agencies that administer affordable and fair housing, public assistance, and health care programs?

For all of those things, Hillary’s history shows that she will get the work done. It matters to have tangible wins — to show people government works in concrete ways, to keep building that bigger majority for progressive public policies and for a muscular government on the side of equality.

Another progressive elected official and Hillary supporter, New York State Attorney General Eric Schneiderman, has written smartly in The Nation about the difference between “transactional” politics and “transformational” politics. For transformational politics, you need concrete victories — and then you keep organizing.

If you read Bernie’s interview with the Daily News editorial board, you have to wonder about whether he can really get the actual, hard, concrete, consequential job of President done well.

I look forward to the day when we can elect a movement progressive (preferably a woman and/or a person-of-color) to the White House, confident that they will lead a first-rate team to do a great job running the country, in a messy and complex world. But honestly, as good an organizer as he has been, do you really see the evidence Sanders would actually be a good President?

And finally, as the proud husband of a Planned Parenthood executive, and the father of a daughter inspired to action by Malala — well, it’s about time. How can I look my daughter in the eye and tell her she can be anything she wants — that I genuinely believe women are fully equal, and am truly committed to fighting patriarchy — if I can’t support Hillary for President in this election?

Electing Hillary isn’t going to bring gender equality, of course, any more than electing Barack Obama eliminated systemic racism. But especially at a time when Trump is revealing just how deeply entrenched racist and sexist attitudes are, it matters to elect women and people-of-color as our leaders.

Bernie is right about this: it is not enough to elect a President to bring the change we want. But we aren’t going to bring about a “political revolution” through a Presidential election, no matter whom we elect. The work of building a new American majority for more progressive policies runs through the long, hard work of organizing.

Perhaps some believe there is a shortcut: Susan Sarandon seemed to suggest that electing Trump might “bring the revolution.” And I understand why some Bernie supporters hope their votes for him will get us there.

But I think we’ll have to keep doing the hard work of organizing, step-by-step, to win better policies that give more people a stake, so that a majority of Americans will see the values of progressive policies … and then join us in pushing for even more.

Sometimes, we will be organizing with President Clinton, to help win policies she will be championing.

Sometimes, as we did this week on issues of public housing, we will call on her to pay attention to an issue she’s been overlooking (this week, she responded quickly, the first one of the candidates to do so).

And many times, for sure, we will be fighting against President Clinton. I’ve disagreed with Hillary many times in the past, and I know I will in the future. The stubbornness of entrenched interests, the urgency of climate change, and the power of concentrated capital will all demand that we keep organizing.

But her nomination as the Democratic candidate, and her election as President, will put us in the best position to keep pushing for — and winning — real, concrete, meaningful change. And then to move on and organize for more.

So I promise to join the rest of the Brooklyn Jewish democratic socialists — and many other varieties of progressives — to keep organizing for justice.

On April 19th, I hope you’ll join me in voting for Hillary.