By Mary Ellen Godin

CRANSTON, Rhode Island (Reuters) - A Rhode Island school prepared for a boisterous public debate on Thursday over a federal court order to remove a prayer banner hanging in the auditorium for nearly half a century, the latest local flare up in the national debate over the separation of church and state.

The public hearing on whether to appeal the court ruling follows heated exchanges between people who want to keep the banner on display in the auditorium of Cranston High School West and those backing a Cranston student, an atheist, who requested it be taken down.

A federal judge ordered last month that school officials remove the 8-foot high by 4-foot wide prayer banner that dates to about 1963 from the wall, agreeing that religious expression should be kept separate from a public school.

The prayer banner reads: "Our Heavenly Father, grant us each day the desire to do our best, to grow mentally and morally as well as physically, to be kind and helpful to our classmates and teachers, to be honest with ourselves as well as with others, help us to be good sports and smile when we lose as well as when we win, teach us the value of true friendship, help us always to conduct ourselves so as to bring credit to Cranston High School West. Amen."

Complaints about the banner first surfaced in 2010 and the student, Jessica Ahlquist, later escalated those concerns with a lawsuit and online Facebook discussion page.

Ahlquist, now a junior in high school, said a friend first pointed out the banner during her freshman year. According to court documents, she experienced feelings of exclusion and ostracism because of the prayer.

Ahlquist was raised Catholic as a child, but around the age of 10 she became an avowed atheist, court documents said.

Rhode Island is among the most Catholic states in the nation. Some 43 percent of the adult population of the two states of Connecticut and Rhode Island identified with Catholic traditions compared with 24 percent nationwide, according to a Pew Forum on Religion and Public Life published in 2008.

The emotional battle over the prayer banner and separation of church and state is one of a host of so-called "culture war" issues gaining attention during an election year. They range from the clash of President Barack Obama's administration with the Catholic church on birth control, to the uproar over a breast cancer foundation cancelling funding to Planned Parenthood because it provides abortions, and approval of same sex marriage by several state legislatures.

Although Ahlquist has received some support, she has also been taunted for even suggesting the prayer banner be altered or removed, court records show.

Many of those who want to keep the mural in place have cited their strong Catholic religious beliefs, while others have said the banner conveys respect, moral values and the history of the school.

Despite arguments the banner had a predominantly secular purpose, a federal judge ruled it to be a prayer "and a Christian one at that," according to court documents.

The prayer has been covered with wood until the school committee decides whether or not to appeal the ruling. A vote was expected to come following Thursday's open hearing.

If the school committee does not appeal the ruling, it is required to immediately and permanently take down the prayer.

(Additional reporting By Lauren Keiper; Editing by Paul Thomasch and Greg McCune)