Final answer:
License revocation for underage individuals convicted of driving with alcohol in their system varies by state, but federal influence ensures severe penalties.
Step-by-step explanation:
The specifics of license revocation for individuals under 21 convicted of driving with any amount of alcohol in their system can vary by state due to the Twenty-First Amendment's delegation of regulatory authority to the states. However, the federal influence is strong due to the National Minimum Drinking Age Act of 1984, which required states to raise their drinking age to twenty-one or face a reduction in federal highway funds. The revocation period can therefore be influenced by state laws but is typically severe to discourage underage drinking and driving.