PELLA, Iowa - Turmoil in Pakistan has moved foreign policy to the forefront of the presidential campaign in the United States, a potentially unwelcome development for two Republican former governors with thin credentials on world affairs.

Mike Huckabee, who spent a decade at the helm in Arkansas, and Mitt Romney, who served one term as Massachusetts governor, have faced questions over the last few days about whether they have adequate experience to lead the country during an international crisis. They are in a tight race in Iowa, with caucus voting on Thursday.

"The most important thing people need to know is that you have the judgment to deal with the issues that confront you," Huckabee told reporters Friday, brushing aside the notion that his diplomatic resume lacks heft. "I understand something about the way the world works."

Yet missteps have hurt Huckabee's efforts to make that case as rivals hammer him on foreign policy. He has struggled to explain his comments on the assassination of former Pakistani Prime Minister Benazir Bhutto and the resulting upheaval in her country.

In Orlando, Fla., on Thursday, Huckabee expressed "our sincere concern and apologies for what has happened in Pakistan." Amid criticism, his campaign said he meant to say "sympathies" not "apologies." He also referred to martial law "continuing" in Pakistan - though the state of emergency was lifted two weeks ago.

Huckabee also linked the Pakistan situation to illegal immigration in the United States, advocating "an immediate, very clear monitoring of our borders and particularly to make sure if there's any unusual activity of Pakistanis coming into the country."

He did the same Friday in Iowa, arguing before a standing-room crowd at a pizza parlor that Pakistan's instability underscores the need for the United States to build a fence on its southern border to combat illegal immigration. Afterward, he sought to explain to reporters how the two issues fit together.

"I am making the observation that we have more Pakistani illegals coming across our border than all other nationalities except those immediately south of the border," he said - repeating an assertion he made to his audience. "And in light of what is happening in Pakistan it ought to give us pause as to why are so many illegals coming across these borders."

He told his audience that 660 Pakistanis have come into the country illegally because of insecure borders.

Pressed by reporters where he got that figure, Huckabee said: "Those are numbers that I got today from a briefing, and I believe they are CIA and/or immigration numbers." Later, in a conference call with reporters, he identified the figure as coming from the Homeland Security Department.

Homeland Security figures for 2006 show that many more illegal immigrants came from India, South Korea, China and Vietnam than Pakistan, which didn't even make the chart.

Romney, for his part, responded to Bhutto's assassination on Thursday - and to any idea that he's weak on foreign policy - by playing down the need for a president to be well-versed in international issues.

"If the answer for leading the country is someone that has a lot of foreign-policy experience, we can just go down to the State Department and pick up any one of the tens of thousands of people who spent all their life in foreign policy," he said while campaigning in New Hampshire.

Instead, Romney said, what is needed is a chief executive with leadership and the ability to assemble "a great team of people to be able to guide and direct them to understand what decision has to be made."

Candidates who run for president from statehouses seemingly always get tagged as weak on foreign policy. They tend to combat the notion by arguing that their experience running a state and handling unexpected crises qualifies them to be president. For good measure, they usually contend that they will surround themselves with advisers strong on foreign policy.

George W. Bush, a Texas governor, overcame the stigma and has been in the White House since 2001. So did Bill Clinton, a Democrat and former Arkansas governor, and Ronald Reagan, a Republican and onetime California governor.

Among Democratic presidential contenders, New Mexico Gov. Bill Richardson might benefit from the shift in focus to international affairs. A former ambassador to the United Nations, he had a specific proposal for dealing with the volatile Pakistan situation.