Some Republican consultants want Trump excluded from debates

“His involvement in any televised debate will be damaging,” said Matt Mackowiak, a Republican strategist based in Texas. “It is my sincere hope that he is blocked from participating.”

“He’s a very toxic addition to the field,’’ said Katie Packer Gage, deputy campaign manager of Mitt Romney’s 2012 presidential campaign.

Mr. Trump so far has been invited to a number of GOP candidate forums, including one sponsored by the conservative website RedState slated for early August in Atlanta. Erick Erickson, the editor in chief of RedState, said he had concerns about including Mr. Trump but extended an invitation.

“We invited him yesterday,” Mr. Erickson said. “I like him. … There is a level of the conservative base who like him. My concern is that I don’t want the other candidates to be overshadowed by Trump.”