Actually, believing that Islam is a peaceful religion, as he does, IS inviting them in.
Facts...
http://www.jpost.com/International/Article.aspx?id=255538&R=R4
http://www.csmonitor.com/World/Americas/Latin-America-Monitor/2011/1123/In-debate-Romney-Perry-warn-of-Islamist-terrorists-in-Latin-America.-Are-they-right