Appearing before the Senate Armed Services Committee for his confirmation hearing, Mattis said the United States is still at war in Afghanistan and American troops are fighting against ISIS and other terrorist groups in the Middle East and elsewhere.
"Russia is raising grave concerns on several fronts and China is shredding trust along its peripheral. Increasingly we see islands of stability in our hemispheres, democracies here in Europe and Asia under attack by non-state actors and nations that mistakenly see their security in the insecurity of others," he said.
The US, he said, has a long list of times when it has tried to engage positively with Russia.
"We have a relatively short list of successes in that regard," he said.
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"I think right now the most important thing is that we recognise the reality of what we deal with Putin and we recognise that he is trying to break the North Atlantic alliance and that we take the integrated steps, diplomatic, economic, military and the alliance steps, the working with our allies to defend ourselves where we must," he said.
"There's another piece of wisdom from antiquity that says, fear, honour and interest always seem to be the root causes of why a nation chooses to go to hostilities," he said.
"I would just say that what we've got to do is engage diplomatically, engage in terms of alliances, engage economically and maintain a very strong military so our diplomats are always engaging from a position of strength when we deal with a rising power," he added.
Mattis agreed that Iran's regional belligerence and nuclear ambitions are a shared threat, both to the US and Israel.
During the hearing, he emphasised on the need for the US to maintain a safe and secure nuclear deterrent, a decisive conventional force while maintaining an irregular capability is completely understood.
"Generally speaking, we would use military as a deterrent role, as a reassurance to our allies, and certainly in most cases as a last resort. So, the role of the secretary of Defence is a broader portfolio than that of a military officer," he said.