Wisconsin Gov. and Republican candidate for president Scott Walker on Friday detailed his foreign policy during a speech in South Carolina. Pictured: Walker speaks at an education summit in Londonderry, New Hampshire, Aug. 19, 2015. Reuters

Republican presidential hopeful and Wisconsin Gov. Scott Walker used a speech Friday in South Carolina to criticize the foreign policy of U.S President Barack Obama’s administration for what he sees as being a retreat from American leadership abroad. In an address at The Citadel, the Military College of South Carolina, in Charleston, Walker outlined his foreign policy, focusing on the Islamic State group, also known as ISIS, which described as one of world's greatest threats.

"At the very least, you deserve a commander in chief who tells you the truth,” Walker said. "And here it is: We are at war with radical Islamic terrorism. It will not go away overnight. This is a generational struggle. And these radical groups will continue to grow if we do not destroy them.”

Walker expressed displeasure with the Iran nuclear agreement, saying it would help Iran expand its influence across the Middle East. He continued to criticize Obama as well as Democratic presidential hopeful Hillary Clinton, saying that when Clinton was secretary of state, the U.S lost its leadership status.

"Confronted by these two forms of evil, President Obama and Hillary Clinton seem to believe they can sit on the sidelines, hoping Iran will defeat ISIS for them,” Walker said. “They fail to realize that, in the prevailing anarchy, the two sides feed off of each other, growing stronger at the expense of our Sunni and Shia allies trapped in the middle.”

Walker also said Clinton ignored China’s record of human rights violations and has tried to appease Russian President Vladimir Putin. Walker has said on the campaign trail that the U.S. needs to be tougher on China.

If he were elected to the White house, he said, one of his goals would be to defeat ISIS. Recruiting and supporting fighters in Syria and enforcing a no-fly zone would be key to the fight, he said.

“These strategic objectives will guide our military commanders, but let me be clear: Defeating ISIS and rolling back Iran will require a greater investment of U.S. resources,” Walker said. “As we learned in the surge, embedded American advisers are key to training and motivating Iraqi, Sunni tribal and Kurdish allies. They can provide good intelligence, logistical resources and call in close air support to direct devastating strikes that will bolster our partners on the ground.”

Walker said the U.S. needs to address border issues, specifically relating to the country’s southern border. He also said the U.S. should restore more counterterrorism and surveillance programs to find terrorists inside the U.S.

“Islamic extremists and other terrorists are most likely using the same trails into our homeland as the drug cartels, weapons smugglers and human traffickers,” Walker said. “We must secure the border at any cost.”

Walker has been a constant critic of Obama’s foreign policy, but his own critics have said he lacks foreign policy experience. He also has been criticized for saying he that if he could handle protesters in his own state, then he'll be able to handle ISIS, referring to Wisconsin residents who protested his moves to limit the power of unions in the state. He later denied comparing the two.

Earlier this year, Walker showed support for sending troops to fight ISIS, saying in February he was willing to put U.S. forces on the ground to combat the militant group. But in June, he said U.S. forces weren't needed to fight ISIS, and that Iraqi forces already there have the capacity to fight the group.

"Clearly, we can no longer afford to be passive spectators while the world descends into chaos. With all of the challenges that we face around the globe today, now is not the time for untested leadership," Walker said. "I have been tested like no other candidate in this race."