South African Navy Rear-Admiral Robert Higgs, the commission's second witness, was led in submitting evidence by Simmy Lebala on Wednesday.
Higgs was requested to explain the link between the role of the military, the use of force, and the SDPP, commonly referred to as the arms deal, in light of the Constitution.
"The use of force is fundamental to any military which must defend and protect South Africa in accordance with the rules of war, the Geneva Convention, our Constitution, and broad international examples of professional militaries.
"We are not out of step with other democracies which have their own militaries," he said.
Higgs, a naval officer for close on 40 years, said he believed the ethos of the South African National Defence Force's (SANDF) mandate had guided the processes which led to the controversial arms deal.
"The ethos [of the SANDF's code of conduct], Mr chairperson, I believe, was fully embraced by all serving military people who participated in the Defence Review and all associated processes to come up with the fact that we needed certain equipment."
Lack of equipment
The previous witness, Rear-Admiral Alan Green, told the commission on Tuesday that the newly-formed SANDF had been crippled by a lack of equipment.
The military officers are addressing the commission on the rationale behind the SDPP and the utilisation of the equipment acquired.
When the new dispensation came in 1994, the SANDF was established in place of the old SADF.
"We were then in a position where all of us were integrated into the SANDF," Green said.
"The primary equipment we had at the time was from the SADF and that equipment was at the end of its life cycle. That was due to the sanctions that were imposed on the country prior to '94."
After democracy, there was a need to rejuvenate the defence force's equipment.
"During that period I served in the navy and I don't have first-hand information about the precise state of equipment in the air force.
However, I was aware that they also required rejuvenation," said Green.
"Any equipment used extensively requires extensive maintenance – our equipment had been extensively used both at sea and in the air. That is why I said there was dire need for equipment."
President Jacob Zuma appointed the commission, chaired by Judge Willie Seriti, in 2011 to investigate alleged corruption in the 1999 multibillion-rand arms deal.
Higgs, the commission's second witness, said South Africa's investment in maritime equipment had been exceedingly modest.
"People know very well about nations moving across the sea and imposing their will on other nations in an unfriendly manner. Often, South Africans need to be reminded of the Anglo-Boer war.
"The British brought almost half a million soldiers to kill the Boers. Those troops came by sea because Britain controlled the seas," he said.
The navy, partnering with other divisions, such as the air force, was well-positioned to fend off an invasion.
"The reality is, our navy is there to make sure that if the British are here, it is because we want them to be here. Not because they will enforce their will on us.
"The ability to protect South Africa against any would-be aggressor is the fact of our maritime trade. It is so fundamental to the butter side of the guns and butter debate," said Higgs.
Through the strategic defence procurement package (SDPP), the South African Navy had acquired four frigates and three submarines.
"If you take a look at it, it is exceedingly modest of us to invest so modestly in what we have put to defend our resources. Four frigates and three submarines, I think that's exceedingly modest.
"We have got to look at our interests and capitalise on those interests. If you don't patrol, you don't control. We have got to be out there and ensure that we retain sufficient expertise. We need staff out there," he said. – Sapa