"I think he would be a very reliable, conservative Republican vote," said state Sen. Tom Harman (R-Costa Mesa).
Vacating the seat is Republican Van Tran, who was in a dead heat in his race against incumbent Rep. Loretta Sanchez (D-Garden Grove).
The 68th Assembly District includes Costa Mesa, Westminster, Garden Grove and some surrounding areas.
Nguyen, a 33-year-old businessman from Little Saigon, sought to capitalize on high Vietnamese turnout for Tran's race. Vietnamese account for about 20% of voters in the Assembly district, and they may have voted for Nguyen because he's more aligned with their issues, according to veteran political consultant Allan Hoffenblum.
During the campaign Nguyen criticized Mansoor's immigration policies as divisive. With promotional visits to mosques, temples and other multicultural venues, Nguyen sought to portray himself as a unifier.
The most controversial issue Mansoor addressed during his tenure was illegal immigration. Long before Arizona passed Senate Bill 1070, he introduced his own measure in 2005 to have Costa Mesa police officers check the immigration status of suspects. In April, he announced that Costa Mesa would not tolerate illegal immigrants. It isn't a "sanctuary city," he proclaimed, but a "rule of law" city.
Nguyen's family came from Vietnam and has an inspiring rags-to-riches story.
While Nguyen grew up in a modest house in the 68th District, he had moved into high-end gated Santa Ana neighborhood, in the neighboring district. The Daily Pilot reported in September that Nguyen may not have lived in the 68th Assembly District when he registered to vote there or filed his papers to run for Assembly.
The district attorney's office, at the time of the election, had not yet determined if it would open an investigation, according to spokeswoman Farrah Emami.
Mansoor apparently didn't need that investigation to overcome Nguyen. He had reliably Republican district — in the 2008 general election 42% of registered voters were Republican and 33% Democratic.
"It will certainly be a new challenge," Mansoor said.