Fewer words are better known in America’s founding documents than the start of the second paragraph of the Declaration of Independence, “We hold these truths to be self-evident, that all men are created equal…” And yet the reality of how this looks in practice is far from utopic.

From the battles over slavery to the immigration rhetoric today — questions of equality and rights under the US Constitution have been consistently divisive and fraught. Today, the Supreme Court upheld 128 years of precedent interpreting the Fourteenth Amendment that, yes, all people born in the United States, regardless of their parentage, are American citizens.

The decision largely rested on the interpretation of the clause “and subject to the jurisdiction thereof”, which President Trump’s team argued meant excluding people with an allegiance to a different country (where they are domiciled). Arguing for the majority Chief Justice Roberts rejected this interpretation, saying “nearly everyone within the territorial boundaries of the United States was ‘amenable to’ the Nation’s jurisdiction.”

While the United States’ version of birthright citizenship originates in British law, it was not until after the Civil War and the end of slavery that Americans enshrined it in their Constitution. In their dissent, justices Clarence Thomas and Neil Gorsuch interpret much of the language in the Fourteenth Amendment and Civil Rights Act of 1866 (US) centred around the citizenship of former slaves and their children and note the language of the Civil Rights Act (US) that citizenship was guaranteed to persons who were “not subject to any foreign power.”

In a separate dissenting opinion, Justice Alito takes up issue with the whole premise of deriving the jus soli (right of the soil) principle of citizenship, derived from English common law. He notes, “it is ironic that the Court should embrace it only days before we celebrate the 250th anniversary of our Declaration of Independence, which emphatically renounced the foundation on which the British rule rested.”

Unrestricted birthright citizenship is only available in 36 countries, 30 of which are in the Americas. No European nation offers birthright citizenship, and Australia ended the practice in 1986.

As we approach the United States’ semiquincentennial, this ruling reaffirms a more expansive view of who is considered a citizen than we see in most countries around the world. However, this will likely set off new debates within the United States. While most Americans say they support birthright citizenship for people whose parents have a legal right to be in the United States, public opinion is evenly split on whether citizenship should be granted to children whose parents immigrated illegally.

Responding to the ruling, President Trump said it was "bad for our Country, but we can easily make it up in Congress through Legislation.” If a legislative pathway is pursued, this issue is likely to become a significant point of contention. In this way, the decision is far from the end and is likely to be the beginning of a significant debate in the years to come.

Read the full US Supreme Court decision here.