(RNS) With political correctness storming the country, I’m waiting for someone to complain about St. Patrick’s Day. After all, it honors a Christian saint who spread his religious beliefs in a foreign land.

Never mind that St. Patrick’s Day is the most widely celebrated Christian feast after Christmas and Easter. Christmas has been secularized: trees are OK, nativity scenes are not. And Easter has, too, with its fuzzy bunnies and pastel-colored eggs. The only difference with St. Patrick’s Day is that secularists haven’t shut down the shamrock business.

At least not yet. I’m waiting.

The shamrock, after all, is St. Patrick’s legendary teaching tool. He used the shamrock to illustrate the Trinity — one leaf each for Father, Son, and Holy Spirit — to the people of ancient Ireland. Some theologians may say his explanation is a little shaky, but it does the job nonetheless.

St. Patrick’s handy shamrock, like the Irish countryside, is green. So is just about everything else every March 17: green ball caps on major league baseball players, green dye in the Chicago River, green clothing on just about everybody.

Somewhere around March 17, the Irish prime minister pays a call on the president at the White House, bearing a bowl of shamrocks. On St. Patrick’s Day itself, the British Army’s Irish Guards wear shamrocks to honor the 5th-century missionary who left his British homeland to carry Christianity to Ireland.

There are parades in Boston and Philadelphia, in Savannah and St. Paul. The parade in Morristown, N.J., recalls when George Washington declared March 17 a holiday to honor the Irish troops in his Continental Army in 1780. And, never outdone, New York City hosts the world’s largest parade up Fifth Avenue, past — of course — St. Patrick’s Cathedral.

Of course it wasn’t always easy for the Irish in New York. The first St. Patrick’s Day “parade” in 1762 comprised a rag-tag bunch of Irishmen — mostly soldiers with British forces occupying New York — to honor their patron saint. Then St. Patrick’s Old Cathedral on Mulberry Street was the focus of the marchers, who sometimes needed military protection from nativist attacks in the late 18th and early 19th centuries. Those days are mostly over, but the original “Fighting Irish” — the 69th Infantry Regiment of the New York Army National Guard — always leads off New York’s parade.

This year, the Empire State Building — construction started on, you guessed it, March 17, 1930 — will again be lit green on St. Patrick’s Day. The lights go off at 2 a.m. on the 18th, ending a powerful lot of celebration in honor of the Christian saint whose green Trinitarian shamrock will be everywhere.

I like it. Happy St. Patrick’s Day.

(Phyllis Zagano is visiting professor of theology and religion at St. Leo University in Florida and author of several books in Catholic studies. She also holds a research appointment at Hofstra University in New York.)