George Washington presiding over the Constitutional Convention, 1787. (AP)

The day got its start in 2005, when the late Sen. Robert Byrd (D-WV) amended an appropriations bill to mandate that federally-funded schools teach about the Constitution every Sept. 17.

The Constitution has enjoyed a surge in interest over the past few years with the Tea Party’s focus on the founding fathers. Last week in South Carolina, Republican candidates pledged to uphold the Constitution, saying the U.S. government has strayed far from its origins.

Meanwhile, a coalition of liberal groups is pushing back, arguing that “the constitutional conservative approach represents a dangerous retrenchment of the government’s role,” Ruth Marcus wrote in a Post op-ed. The “Constitutional Progressives” wants to claim ownership of governing by the Constitution, she wrote.

To better understand why this 200-years-old document matters so much, I called an expert on the matter a.k.a. Robert Bell, my dad.

“I loved Con law [that’s lawyer speak for Constitutional Law] in law school,” he says sounding misty-eyed still, 35 years after his graduation.

So what’s there to love? His reply:

“There’s a lot to celebrate in there. It establishes all the functions of government. It was a brilliant piece of political history, setting up the branches of government with all of its checks and balances.

“The first amendment especially is just a marvel. It’s one of the most important safeguards we’ve got, and very few places have it.

“It’s a really intriguing document and so are the Supreme Court cases whose arguments are well-written and well-thought out on both sides... As a way to found a nation, [the constitution] is a tremendous blessing for us.”

Explore the Constitution here.