Trump calls for higher defence spending after isolationist talk

Republican presidential candidate Donald Trump. Photo / AP

Donald Trump, in a nod to the conservative foreign policy establishment, called today for a robust expansion of US military capabilities and an end to automatic budget caps on defence spending.

It is a sharp departure for a Republican nominee who has clashed with his party's military hawks over the necessity of foreign interventions.

Trump's address represented his most substantive and comprehensive plan on US national security to date - part of an ongoing effort to assuage doubts that he lacks a sufficient understanding of policy issues to assume the presidency.

The remarks also cheered many GOP lawmakers on Capitol Hill who have been wary of Trump's repeated vows to retreat from international military commitments and focus more resources on domestic problems.

In his remarks, delivered at the Union League in Philadelphia, Trump said his proposed expansion would be made possible in part by bringing an end to Pentagon spending limits implemented in 2011 and known as sequestration.

"As soon as I take office, I will ask Congress to fully eliminate the defence sequester and will submit a new budget to rebuild our military. It is so depleted. We will rebuild our military," Trump said.

"This will increase certainty in the defence community as to funding and will allow military leaders to plan for our future defence needs."

The speech came ahead of NBC's Commander-in-Chief forum, the first event to feature both presidential candidates since they won their parties' nominations. The forum, broadcast by MSNBC and NBC stations and hosted by Matt Lauer, was billed as a discussion of the most important issues facing the nation's next commander in chief. The two rivals appeared separately before a live audience at the Intrepid Sea, Air and Space Museum in New York at an event hosted by the Iraq and Afghanistan Veterans of America.

Yesterday, Trump announced that he had been endorsed by 88 retired senior military officials. Not to be outdone, Clinton released a list showing the support of 95 retired generals and admirals - more than any other recent non-incumbent Democrat, her campaign said. Clinton noted that Trump's endorsement figure was more than 400 shy of that of the previous Republican nominee, Mitt Romney.

Trump's speech marked a striking shift towards conservative orthodoxy for the real estate developer, whose foreign affairs message was built on an anti-establishment, anti-interventionist posture.

Trump has often dismissed the value of consulting experts on international relations, pointing to upheaval in the Middle East as proof that their policies have been ineffective. In discussing Isis last northern autumn, he asserted that he knew "more about Isis than the generals do".

He also notably reversed his support for budget sequestration, which he previously suggested had not gone far enough. His direct appeal to expand spending also upended earlier claims that the military could strengthen its core functions with less money, though he provided no price tag for his new proposals nor a clear means to pay for them.