The correct answer is the 14th Amendment.
It states that "All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."
Specifically, your referenced quote is known as the "Equal Protection Clause"
The supreme court extends its powers by their decisions which sets a precedents knows as case law. This law is followed when lower courts make decisions. It decides if the laws congress is making are constitutional or if they can be overturned.
The Carolingian Empire covered much of the Western and Central Europe but it collapsed in less than hundred years after the death of Charlemagne in 814. Several factors led to the fall of the Carolingian Empire. The division of Frankish lands among the male members of the Carolingian dynasty was a major factor. The Carolingians extended their rule over most Western and Central Europe in less than one half of a century and became regarded as the renewers of the Roman Empire after the Imperial coronation of Charlemagne in 800. The Carolingian Empire achieved its greatest territorial extent during the reign of Charlemagne (768-814) who added Lombardy, Saxony, Danubian Plain and Spanish March to the Realm of the Franks. However, Charlemagne’s empire started to decline already under his successor Louis the Pious (814-840) and collapsed by the end of the 9th century.
