KĀNE'OHE BAY — Marine Corps Gunner James Law was a tender-talking dad one minute and tough-as-nails Marine the next.

"Be nice to your sister, OK?" the tall Marine said soothingly yesterday to his oldest daughter, Caroline, 5, as the blonde girl clung to his leg.

Once Law said goodbye to his wife, Regina, who is pregnant, and their three daughters, he went into deployment mode. He's been through this many times, and he knows how to switch his focus quickly.

"It's always easy, my friend. You just keep your head on a swivel and you do your job."

Law and about 1,000 other Hawai'i Marines are headed to Afghanistan, and after two previous tours to Iraq and one prior mission to Afghanistan, the 36-year-old's philosophy is simple: Keep your mind on the mission so you can come home to family.

"If you cry and moan about family, you (can) get hurt," the Portland, Ore., man and 18-year Marine said.

"He loves what he does," said Regina Law, who blew a kiss to her husband as he sat on a bus. "He's absolutely made to do what he's doing right now."

About 380 Marines with the 3rd Battalion, 3rd Marine Regiment, left yesterday for Joint Base Pearl Harbor Hickam and a series of flights that will take them to Afghanistan for seven months of duty in Helmand province in the south.

About seven months ago the battalion returned from Iraq.

Since 2004, "America's Battalion," as it is known, has deployed to Afghanistan, Iraq three times, and now back to Afghanistan.

The three infantry battalions at Kāne'ohe Bay now rotate through deployments to southern Afghanistan. The 3rd Battalion will replace the 1st Battalion, which has lost five Marines since it deployed in November.

Afghanistan has become the Marine Corps' main challenge with the Iraq war winding down.

Battalion commander Lt. Col. Jeff Holt, 40, is confident. "We know what we're doing," Holt said at yesterday's pre-deployment gathering of Marines, families and gear near the commissary and base chapel. "We're certainly well trained. We've had a great pre-deployment training workup. So we look forward to going over there and doing what we do as Marines."

Nine years into the war, experts are divided on President Obama's counterinsurgency strategy, which places a premium on protecting the Afghan people.

According to an April report to Congress, as of March 31 there were about 87,000 U.S. troops in Afghanistan. That total is expected to increase to 98,000 by August.

The progress report said polls show that Afghans see security as improved, but violence is up from a year ago. Insurgents perceived 2009 as their most successful year, and the Afghan insurgency "has a robust means of sustaining its operations," the report said.

Nawa, in central Helmand where Hawai'i's 1st Battalion Marines operate and the 3rd Battalion will take over, is seen by some Afghanistan experts as having reached "hold" and "build" phases of the U.S. "clear, hold and build" counterinsurgency strategy.

Helmand is a poppy-producing region and the profits of that trade have financed militants. Holt said the region has about 90 percent wheat and 10 percent poppy production.

Efforts are being made to encourage the growth of crops such as wheat and pomegranates, Holt said.

"That's the challenge of Afghanistan," he said. "They can grow anything ... but to not get taxed on the roads and to get it moved quickly is a challenge that most Afghans have."

Yesterday's pre-deployment gathering showed how many relatively new Marines are part of infantry battalions and are making their first trip to a war zone.

About a third of the 1,000-Marine battalion is made up of returning veterans of overseas deployments, while two-thirds of its members are on their first deployment, Holt said.

"One-third is a whole (lot) of experience — folks that have done Afghanistan before, have done Iraq before and understand the environment of counterinsurgency," he said.

First Lt. Michael Bishoff, 26, has been a Marine for about three years. He's making his first combat deployment.

"This is what I signed up to do, and I'm looking forward to doing it," the Mississippi man said.

Mary Stokes looked on tearfully as her husband, 24-year-old 1st. Lt. Jason Stokes, sat on the white bus that would take him to Hickam.

The Florida couple has been married for nine months.

"Hardest thing I ever had to do," she said. Stokes added she was "just anxious more than anything. Of course I'm worried, but I know he's going to do a good job."

How does her husband feel about going to Afghan- istan?

"He's stoked. He's ready," she said.