Not to get all Clintonian here, but it depends on what you mean by “tourism,” “federal government,” and “biggest.”
The tourism-marketing organization Destination D.C. says visitors pump more than $5 billion into the city every year. But it’s hard to slap a jobs figure together, given that residents also patronize the stores, restaurants, and museums where tourists spend money. Destination D.C. puts the number at 67,000 jobs “supported” by tourism, which could just mean working in food service downtown. (This is why the sector is usually referred to as “hospitality” instead).
It’s just as hard to tease out the federal factor. Quite a bit of the District’s “private sector,” from lobbyists to government contractors, is wholly dependent on the feds. So even though there are 209,000 federal employees in the District, according to the Department of Employment Services—by far the biggest chunk of the 711,000 jobs the District averaged in 2010—lots of employees in “professional and business services” wouldn’t be here if Uncle Sam weren’t nearby. The same goes for many of the 32,500 people employed in the “legal services” sector.
So what’s left over? Nothing that exports anything, that’s for sure. The District was never a manufacturing town; a measly 11,700 “goods producing” jobs remained in 2010. On the other hand, the century ahead looks bright for the sector known as “eds and meds.” Some 60,000 D.C. workers are employed in health care, while education has 48,400 jobs. Both categories are expected to keep growing. It’s pretty unlikely that would change if D.C. became a state.
Of course, especially now that the federal backstop is starting to look so shaky, the city would like to see more exciting industries grow faster—small tech startups, say, or financial and insurance businesses. But right now, taking care of peoples’ bodies and brains is what’s keeping D.C. employment afloat. So go to those occupational therapy appointments, and consider getting another degree. It’s practically a proud District resident’s duty.