Senator McCain spoke in mid-April at Columbia,
at the beginning of his "Straight Talk America" series of

The University could have refused to host him, for he had only
"suspended" his candidacy. Had he been a candidate, he could not
have spoken unless the sponsoring organization paid his fee, as
well as the costs of security and technical coverage of the
event. Tax-exempt organizations host office-seekers at the risk
of losing their tax exemption.