ORLANDO -- In the presidential primary, Mitt Romney seized a hard line on immigration, but Thursday before an influential group of Hispanics, the Republican nominee made a careful turn toward the middle.

He called for permanent residency for highly-skilled college graduates and members of the military, and protections for families snared in the vortex of current law, but also a“high-tech” fence to enhance border security.

“We can find common ground here, and we must,” Romney said, striving to attract support from a crucial and growing voting force. But Romney, who called attention to President Barack Obama’s failed promise to tackle comprehensive immigration reform, left unclear how he would respond to Obama’s surprise announcement last week that he will block the deportation of young illegal immigrants and grant them work permits.

“Some people have asked if I will let stand the president’s [order],” Romney said. “The answer is that I will put in place my own long-term solution that will replace and supersede the president’s temporary measure. As president, I won’t settle for stop-gap measures.”

Nor did Romney address the most vexing immigration problem: What to do with the more than 11 million undocumented residents already living in the United States. Previously he has said he would veto the Dream Act providing a path to citizenship to some illegal immigrants who arrived in the country as minors. He has advocated the undocumented immigrants should “self-deport.”

The balance reflects the difficulty of the immigration issue as Romney tries to broaden his appeal without alienating conservatives. Romney has tried to largely avoid the issue since the primary, focusing exclusively on the economy. Appearing here Thursday, a day before Obama, Romney was under pressure to say something and he offered up a lengthy policy outline, even if it lacked specifics.

It’s unlikely Romney changed many minds among the heavily Democratic National Association of Latino Elected and Appointed Officials, which greeted him with tepid applause (and a few boos when he mentioned repealing the health care law).

“You’ve got to look at the last year. Would he be saying these same things in Iowa to a bunch of white faces? No, he wouldn’t,’’ said state Rep. Darren Soto, D-Orlando. “You can’t go from a year’s worth of anti-immigration bashing to an about face here and expect everybody to believe you.”

Some of Romney’s proposals were well received — chiefly those aimed at immigrant families — and critics conceded his focus on improving the economy could resonate among a population that faces 11 percent unemployment vs. the 8.2 percent unemployment among overall workers.

“Almost four years ago, the American people did something that was very much the sort of thing Americans like to do: We gave someone new a chance to lead; someone who we hadn’t known for very long, who didn’t have much of a record but promised to lead us to a better place,” Romney said.

His proposal calls for permanent residency for highly skilled college graduates and members of the military; a streamlined work visa system; giving legal permanent residents the same priority as citizens when applying to bring husbands, wives and minor children to the United States; and re-allocating green cards to family of citizens and legal permanent residents.