BostonGlobe.com Political Headlines - July 23, 2012

Here are the top POLITICAL headlines on BostonGlobe.com from the weekend and today:

• Bloomberg says candidates should debate gun control: Mayor Michael Bloomberg of New York on Sunday called for President Obama and presumptive Republican nominee Mitt Romney to lead a national debate about gun control, so far a nonissue in the presidential campaign. Political correspondent Callum Borchers writes.

• A business built on hard work - and government: Mitt Romney put a gloss on the truth about Middlesex Truck & Coach during a visit to the Roxbury business. Columnist Joan Vennochi writes. 

• Romney changed stance on gay rights, Boston group says:   The lesbian, gay, bisexual, and transgender publication Bay Windows wrote this week that Mitt Romney has turned his back on their concerns. Political correspondent Callum Borchers.