ROSEMONT, Ill. — An imam of a mosque in New York City and his associate shot dead while strolling following afternoon prayers. A presidential candidate calling for Muslims to be barred from entering the United States. Muslim women harassed and physically attacked in Chicago while walking to their car.

During the Islamic Society of North America convention that started here on Friday, official speakers said these actions had become all too commonplace in the United States.

“In this political climate, we’ve seen a normalization of bigotry,” said Altaf Husain, an associate professor at Howard University and a vice president of the society, whose convention here is the largest Muslim gathering in the United States and Canada.

But Mr. Husain, expressing what he said was the sentiment of many other American Muslims, said the Obama administration had made it a priority to bolster engagement with Muslims across the country. The latest example of the administration’s engagement came Saturday night when Jeh Johnson, the secretary of Homeland Security, became the first sitting cabinet member to address the Islamic Society’s convention.