Blumenthal and McMahon won their party nominations at conventions Friday for the post that the Democratic senator has held since 1981. Dodd is retiring.
Blumenthal easily captured the nomination despite recent criticism for misstating his military record during Vietnam.
"I have made mistakes. I regret them. And I have taken responsibility," Blumenthal said. "But this campaign must be about the people of Connecticut."
McMahon, once an executive with World Wrestling Entertainment, has acknowledged providing information on Blumenthal's misstatements to the media.
"I venture to say we're going to lay the smackdown on him come November," said McMahon, who has vowed to spend $50 million of her own money in the campaign.
"I was an unknown coming into this race," she said. "I needed to have a good solid campaign out of the box because people need to know who I am and what I stand for."
But before McMahon takes on Blumenthal in the fall, she has to get by former U.S. Rep. Rob Simmons, a Vietnam war veteran with two Bronze Stars. He received enough votes Friday to force an August primary.
McMahon pulled away from Simmons when several dozen delegates at the Republican convention switched their votes before the first ballot became final.
And Fairfield County money manger Peter Schiff, who lost many of his delegates to McMahon, may try to petition his way onto the primary ballot, supporters said.
Despite the national attention that Blumenthal's misstatements have attracted, Democrats said they could not ignore his 26 years of political service
- six years as a state lawmaker and 20 as Connecticut's omnipresent attorney general
- to the state.
Blumenthal sprinted past Mystic businessman Merrick Alpert in the delegate count, leading Alpert to pull out of the contest and Blumenthal winning on a voice vote.
"I do think it's unfortunate he had some of the statements he made, but this convention is with him and everyone is human," said state Rep. Andrew Fleischmann, D-West Hartford.
At the Republican convention, McMahon's husband, Vince, and Paul Levesque, McMahon's son-in-law, who is known to wrestling fans as Triple H, made an appearance. Many of McMahon's supporters painted Blumenthal in the role of bad guy, wearing stickers with Blumenthal's face and the word "Liar."