Sen. John McCainJohn Sidney McCainBiden falters in pledge to strengthen US alliances 20 years after 9/11, US foreign policy still struggles for balance What the chaos in Afghanistan can remind us about the importance of protecting democracy at home MORE (R-Ariz.) is pouring cold water on President Trump's first budget, warning that it won't pass the Senate.
“It is clear that this budget proposed today cannot pass the Senate," the Armed Services Committee chairman said in a statement.
McCain added that as lawmakers work on funding the government, they must come up with a deal "that provides sufficient funds to rebuild the military."
Trump's budget included $603 billion for total defense spending, which includes money outside of the Pentagon, plus an extra $65 billion in overseas contingency funding that is not subject to budget caps.
But McCain argued that the baseline budget for repealing the 2018 fiscal year needs to be at least $640 billon and that lawmakers should start working on defense funding for the rest of the current fiscal year, which expires at the end of September.
"Failure to do so will only lead to more political dysfunction that has inflicted such harm on our men and women in uniform over the past six years," he said.
The House passed a defense appropriations bill last week to fund the department through the end of the 2017 fiscal year.
Any push by Republican defense hawks to increase military spending would likely hit roadblocks in the Senate, where Democrats are demanding equal increases in defense and non-defense spending.
Lawmakers have until April 28 to pass legislation funding the government and avoiding a shutdown.