"They will not get away with attacking my wife in this campaign," McConnell told about 100 home-state supporters at a Republican dinner in Winchester.
"This woman has the ear of @McConnellPress — she's his #wife," the group Kentucky Progress tweeted on Feb. 14. "May explain why your job moved to #China!"
McConnell forcefully defended Chao, who was born in Taiwan and who moved to the U.S. as an 8-year-old with her family aboard a freight ship.
Ashley Judd joins GOP in rebuking Kentucky Progress
"Secretary Chao and her family are shining examples of the American dream: salt-of-the-earth folks who escaped oppression, came here with nothing, joined our great melting pot, worked exceptionally hard to build a thriving business, and then dedicated so much of their lives to giving back," said Jesse Benton, manager of McConnell's re-election campaign. "It is unconscionable that anyone would use blatant race-baiting for political gain."
Progress Kentucky removed the offending comments from Twitter after Louisville public radio station WFPL-FM aired reports about them. And the group issued two apologies over the past week for what they described as "inappropriate tweets sent by our organization."
"Those tweets did not reflect our values, and we are committed to making sure nothing like that happens again," executive director Shawn Reilly said in a statement posted on the group's website. "We also apologize to our many supporters, and all Kentuckians working for change in 2014, for those communications. Comments with references to race, ethnicity or sexual orientation have no place in any debate, and we are deeply embarrassed by such a mistake."
Reilly said the volunteer who posted the comments no longer is affiliated with the group.
Criticism of the group wasn't limited to McConnell and his supporters. Numerous Democratic leaders, including actress Ashley Judd, who is considering a challenge to McConnell in next year's election, spoke up, too.
"Whatever the intention, whatever the venue, whomever the person, attacks or comments on anyone's ethnicity are wrong & patently unacceptable," she wrote in a Twitter message last Sunday.
Kentucky Democratic Party Chairman Dan Logsdon said the comments were "deplorable" and "have absolutely no place" in Kentucky politics.
McConnell and his wife have faced similar slights in the past. In 2001, former state Democratic Party chairwoman Nikki Patton apologized for saying that McConnell "passed up some good Kentucky pork to chow down at the Chinese money buffet."