During his first post-inauguration visit to the Pentagon, President Trump today signed an executive order for what he described as the start of a “great rebuilding of the Armed Forces,” seeking to increase the size of the US military, which already spends roughly as much as the eight next largest militaries in the world.

Trump promised the plan would include new warplanes, new ships, new resources, and in increase in the number of special forces. The order calls for the Pentagon and Office of Management and Budget to work jointly on increasing military spending in the next fiscal year, and in ways that will give the Pentagon chief more flexibility on spending.

Exactly how much bigger the 2018 military budget is going to end up being is unclear, as analysts have estimated things like the planned increase in warships adding a massive amount both in construction costs and in maintenance. At the same time, the Trump plan calls for reducing spending on projects not considered “highest priority.”

That’s potentially difficult, however, as the costliest weapons projects, even those the Pentagon is relatively ambivalent about, tend to carefully spread their spending through enough Congressional districts as to make the cuts politically difficult.

Trump made increasing the size and strength of the military a top priority during the campaign. He is considering several proposals on escalating the fight against ISIS, which is likely to involve an increase in ground troops deployed around the Middle East. This too is likely to increase costs in the final budget.