The tenure of Barack Obama, and indeed the tenure of any president of the United States, is marked by countless decisions.

A few of Obama’s more notable ones include his choice at the outset of his presidency to bring forth the Affordable Care Act, single-handedly reigniting the debate over healthcare reform in this country.

Additionally his recent executive actions on frontline issues like gun control and immigration have made pundits and scholars alike debate the latitude of executive authority.

These decisions — and an entire slate of others — have the potential to shape the national political climate for years after Obama leaves the Oval Office. However, it’s hard to believe that none of them are as momentous as the decision he will make in the near future.

This past Saturday, Associate Supreme Court Justice Antonin Scalia died of a heart attack at a ranch in west Texas.

Widely considered to be the most incendiary and outspoken member of the Supreme Court, Scalia led what the New York Times called a “conservative intellectual renaissance” over his three decades of service on the bench.

Known for his staunch defense of constitutional originalism, Scalia offered what the essayist Margaret Talbot termed “the jurisprudential equivalent of smashing a guitar onstage” with his pugnacious and irrepressible wit that sometimes bordered on the irreverent.

He leaves behind a court that is impeccably split ideologically — with four Justices on each of its conservative and liberal wings.

It is now President Obama’s duty to nominate a successor.

In any given year, Obama’s nomination would be watched carefully, but this choice will almost certainly be met with especially heightened scrutiny.

The Supreme Court’s docket for the upcoming year includes cases that deal with a plethora of contentious issues such as abortion, voting rights, affirmative action, energy and campaign finance. Up until Scalia’s death, it had been thought that this agenda would favor the conservatives as it would likely bring Anthony Kennedy, the court’s swing vote, to the conservative side. But now that potential Republican triumph hangs in the balance.

Unlike his presidency, which inevitably must be devoted to a small nucleus of issues that he is most passionate about, his nomination for the Supreme Court — should it go through, which seems unlikely, given ferocious opposition from leading Republicans at the mere thought of Obama even nominating someone in the first place — will touch all of the issues listed and many more.

Indeed, the man who some believe Obama will nominate, an Indian-American named Sri Srinivasan who has worked for Democratic and Republican Administrations, is only 48years old.

At such a young age (by Supreme Court standards) Srinivasan would not only render judgment on issues currently facing the nation, but would also have input on cases that would extend far beyond Obama’s presidency.

Obama’s dogged pursuit of reform in the areas of healthcare, immigration and gun control — which a few days ago seemed like the most important tasks he could ever undertake — are now mere sideshows.

His nomination for the next Justice of the Supreme Court will without question be the most consequential decision he will ever make as president of the United States.