US President Donald Trump is hailing his 2018 budget brief as a boost to national defense, but conservative hawks are skeptical his proposed increase to the Defense Department is sufficient to rebuild the military.

The White House released its fiscal year 2018 “skinny budget” 16 March, a topline overview of the president’s financial plan. Trump unveiled a $54 billion increase to defense spending, made possible by deep cuts to the Environmental Protection Agency and soft power-focused agencies such as the State Department.

The budget repeals defense sequestration and requests a total of $639 billion for the Defense Department, including $574 billion allocated toward the base budget and $65 billion for overseas contingency operations. The White House claims the base budget number represents a 10% increase from the 2017 level, but Congressional Republicans dispute that figure.

Trump plans to address the Defense Department’s depleted munitions stocks, as well as deferred maintenance and modernisation. The plan promises to accelerate the US Air Force’s efforts to improve its tactical air fleet’s readiness, investment in training systems and procurement of additional Lockheed Martin F-35s.

The proposal would also slash funding for independent agencies that support the arts and humanities, but the Trump administration will find the majority of savings in the State Department, where it plans to cut $10 billion or a 28% reduction. Trump also requests siphoning off $2.6 billion or a 31% reduction from the Environmental Protection Agency.

For Republican Congressional leadership, Trump’s budget does not live up to his bellicose rhetoric. Senate Armed Services Committee Chairman John McCain criticised Trump in a 16 March statement, calling the $603 billion topline proposal insufficient to rebuild America’s military.

“Such a budget does not represent a 10% increase as previously described by the White House, but amounts to a mere 3% over President Obama's defense plan, which has left our military underfunded, undersized and unready to meet the threats of today and tomorrow,” says McCain.

McCain and House Armed Services Committee chairman Mac Thornberry agree on a $640 billion defense budget for fiscal year 2018 plus sustained increases over the years, he adds.

Meanwhile, the White House also submitted a supplemental budget to address the DOD’s urgent needs in fiscal year 2017, with $24.9 billion proposed for the department and another $5.1 billion in overseas contingency operations funding. The 2017 supplemental budget outlines $13.5 billion for procurement and modernisation efforts including additional Boeing AH-64 Apache and Sikorsky UH-60 helicopters for the US Army, Lockheed F-35s, Boeing F/A-18s and other unmanned aircraft. The budget also sets aside $2.1 billion for research and development efforts.