John McCain greets supporters after a rally in Sarasota during the presidential campaign in 2008; by the birther interpretation of the US constitution, McCain – born on a US military base in Panama – would have been ineligible to be US president. Photograph: Carolyn Kaster/AP

Barack Obama was born in the United States. But even if he had not been (as the birthers believe), he would still be the legitimate President of the United States. The birther movement (apparently, now led by Donald Trump) argues that article 2, section 1 of the US constitution ("No person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this constitution, shall be eligible to the Office of President") requires that the Barack Obama of their universe (that is, born "abroad") cannot be the legitimate president.

For the birthers, the translation of "natural born citizen'" is simply "those born inside the United States". To them, anyone born outside the United States is ineligible for the presidency. They are wrong.

First, a little disclaimer: the birther attacks are personal to me. I was born in London to an American father and British mother. While I have a great and abiding respect for the UK (my British grandfather was an RAF officer of whom I am incredibly proud), my ultimate allegiance has always belonged to the United States. My father is a former US diplomat and his father was a career US military officer, whose second world war service included Guadalcanal and Okinawa. I believe that my family heritage has earned my right to be a "natural born citizen" of the United States. And I believe any cogent reading of the constitution supports me in this belief.

While the thinking behind the founding fathers' adoption of the natural born citizenship clause is not clear, most legal scholars assume that the motivating intention was to prevent (English) royalist infiltration of the US government – an understandable concern at the time. Regardless of that, though, in determining the meaning of the clause, we must consider the developed law.

The Naturalisation Act of 1790 provided that "the children of citizens of the United States that may be born beyond Sea, or out of the limits of the United States, shall be considered as natural born Citizens." Just three years after the constitution's adoption, this would seem to give an early and powerful repudiation of the birther reading of the clause. But it cannot, on its own, clarify the constitution.

In United States v Wong Kim Ark, the US supreme court ruled that a child born in the United States to two US domiciled foreign parents not serving with a foreign government was a natural born citizen. This set the precedent that natural born citizenship could be granted by the principle of "jus soli", or citizenship from birth in the United States. However, as illustrated by the Naturalisation Act, jus soli cannot account for all Americans. To fill the space of absent court clarification on American citizens born abroad, Congress has provided statutory definition for natural born citizenship.

Title 8, section 1401 of the US Title Code provides these definitions to include (among other qualifying citizens) those born abroad to one American parent and one foreign parent, provided the American parent spent five years in the US prior to the child's birth. The strength of section 1401 is in its clarification of the clause in a logical manner, compatible with the constitution and in a way that can account for American citizens not physically born in the United States. Because the law grants citizenship even to the Obama of the birther universe, the birthers reject section 1401 as unconstitutional.

In contrast to the logic of section 1401, the birther reading of the natural born citizenship clause is highly problematic. Put simply, if the only natural born citizens are those born inside the United States, then many "natural'" Americans are left out in the cold. The state department foreign affairs manual (pdf) notes that under the constitution's 14th amendment, US government installations abroad are not part of the United States. Therefore, according to the birther approach, this would mean, for example, that while a child born inside the United States to foreign tourists or to illegal immigrants is a natural born citizen, John McCain – born on a military base in Panama – is not.

The absurdity of such a reading of the constitution is profound. Under the birther approach, foreign service and experience are acts to be punished by deprivation of citizenship rights for the children of servicemen and women and public officials posted overseas. How can we honestly believe that the founding fathers would regard the citizenship of children of those who have served their country abroad as less than that of those residing in the United States? To make this argument as the birthers do is illogical and reflective their distorted and deficient understanding of the US constitution.

• Editor's note: as originally published, the title of the supreme court case United States v Wong Kim Ark was mistranscribed; an amendment was made at 22:45 GMT on 25 April 2011