Why is it important to pay federal taxes?

What does this answer mean?

Paying federal taxes is important because it's required by law and it funds the federal government. USCIS accepts four answers: required by law, all people pay to fund the federal government, required by the Constitution (16th Amendment), or civic duty.

The Constitution gives Congress the power to collect taxes to pay the country's debts and provide for the common defense and general welfare. The 16th Amendment, ratified in 1913, added the power to tax income from any source without dividing that tax among the states by population. That's the basis of today's federal income tax.

Tax money pays for the work of the federal government, including the military and many programs and services. Because everyone who must pay contributes, paying taxes is also seen as a civic duty, a responsibility people share as members of the community.

Paying taxes is also one of the accepted answers to "What is one way Americans can serve their country?"

At the interview, the shortest answer is "required by law."