Tanden has notably worked on several Democratic presidential campaigns, including those of Michael Dukakis in 1988, Bill Clinton in 1992, and Barack Obama in 2008. Tanden was a senior staffer to Hillary Clinton during her 2000 election to a United States Senate seat in New York, and during Clinton's tenure as a Senator. Tanden advised Clinton during her run for the 2008 Democratic nomination, and later helped her defeat Bernie Sanders to win the nomination in 2016, and run against Donald Trump in the 2016 general election. In her government service with the Obama administration, Tanden helped draft the Affordable Care Act (ACA).