U.S. Treasury Secretary nominee Janet Yellen on Tuesday steps into a new role following more than a quarter-century in government: salesperson for economic policy after years of defending Federal Reserve thinking and actions.

The Senate Finance Committee’s 10 a.m. hearing Tuesday is likely to feature topics from foreign-exchange policy to taxes, but it will also serve as the first congressional forum where lawmakers will vet President-elect Joe Biden’s $1.9 trillion Covid-19 relief plan. Yellen will tell them that low borrowing costs mean it’s time to “act big,” according to her prepared remarks.

Yellen, 74, will need to sell a package that includes a minimum-wage hike and substantial expansion in family and medical leave -- social safety-net programs that have already triggered Republican opposition. Democratic lawmakers, who will soon enjoy majority control of the chamber, are set to press for their own priorities.

U.S. stock futures rose Tuesday, with contracts on the S&P 500 Index up 0.7% as of 7:45 a.m. in New York, and bond yields ticked up as investors awaited Yellen’s comments.

For Yellen, a former economics professor who’ll become the first woman to run the Treasury if confirmed, it’s a marked difference from previous service as Fed chair and vice chair, and running the Federal Reserve Bank of San Francisco. She also headed President Bill Clinton’s Council of Economic Advisers, which she ran more as an economic think-tank for the administration rather than a group that set policy.

This time she comes to Congress as a political appointee in an environment charged by the possible impeachment trial of Donald Trump and the repercussions of this month’s violence at the Capitol.