Under the most optimistic scenario, the Democrats will win the House and keep 50 seats in the Senate. That’s it. A more realistic scenario has the GOP winning a tiny majority in the Senate. As a result, the opportunities for Harris and the Democrats to do much meaningful legislating will be few and far between.
There is one exception to this rule–the Trump individual tax cuts are expiring next year, which would give Harris considerable leverage with the Republicans in the Senate, who will desperately want to keep them. Would Harris look at the deficit and let them expire, or would she make a deal in which the tax cuts for the wealthy are traded for additional spending on social programs such as the child tax credit?
Harris, like most Democrats (and, for that matter, Republicans) doesn’t seem to care much about the deficit. In addition, Congress has been allergic to difficult tradeoffs for many years. My money is on the second option.