Start with the legal question, not a yes/no verdict
Citizenship law does not fit safely into one binary flowchart. This map is deliberately a routing tool: each branch takes you to the legal framework that must be tested against the person's actual dates and facts.
What could be the source of U.S. citizenship?
Born in the United States?
Start with the Fourteenth Amendment and 8 U.S.C. § 1401.
Open legal frameworkBorn abroad with a U.S.-citizen parent?
Use the acquisition-at-birth statute in effect on the date of birth.
Open legal frameworkCitizen parent before age 18?
Check INA 320, INA 322, or the historical law that applied when the relevant conditions were met.
Open legal frameworkQualifying U.S. military service?
Check INA 328 and INA 329 separately; their requirements are different.
Open legal frameworkLPR married to a U.S. citizen?
INA 319(a) may allow the 3-year route if its spouse and marital-union requirements are satisfied.
Open legal frameworkLawful permanent resident?
INA 316 is the ordinary 5-year naturalization framework.
Open legal frameworkWhy the old diagram was retired
It encoded shortcuts that were not legally reliable—for example, treating any trip over six months as automatically disqualifying, flattening military routes into the ordinary LPR path, and treating “under 18 with a citizen parent” as sufficient for automatic citizenship without status, residence and custody elements. A visual aid should simplify presentation, not simplify away the law.