Poland's first popular presidential campaign officially ended Friday with Lech Walesa enjoying a big lead and underdog challenger Stanislaw Tyminski being booed at his own rally.

Two days before Sunday's vote, the Solidarity chairman was awarded a strong endorsement from the head of the country's Roman Catholic Church, to which more than 90 percent of the population belongs."The Polish church will side with Walesa," Cardinal Jozef Glemp announced. The unusually explicit statement came after a meeting in Rome with Polish-born Pope John Paul II.

"This is not a political decision but a decision based on certainty of . . . the common good for the whole country," Glemp said.

Tyminski was trying to recapture the momentum that allowed him to upset Prime Minister Tadeusz Mazowiecki and capture second place in the first round Nov. 25.

He conducted a strong first-round race even though he was a previously unknown businessman who had just spent 21 years in Canada and Peru.

However, the last state television election poll, conducted Monday and Tuesday, showed Walesa with a 73 percent to 16 percent advantage. Two other polls put the margin at 58 percent to 23 percent and 61 percent to 20 percent.

On his final stop of the campaign, Tyminski told supporters in Szczecin he would not leave Poland again, regardless of the election outcome.