The federal government is using a secret weapon to fight back against pressure from NATO and some allies to increase Canadian defence spending.

That weapon? Figures compiled by the Department of National Defence that show how different countries calculate their defence spending compared to Canada.

Government sources tell The Canadian Press the numbers illustrate how Canadian defence spending totals would be much higher if the government included the same things in its calculations as other NATO countries.

Those countries include spending on operations like the coast guard, some veterans’ benefits, and even federal police forces and border guards — all things the federal government leaves out of its totals.

The issue is expected to be one of the main topics, alongside terrorism, when Prime Minister Justin Trudeau meets Thursday with other NATO leaders in Brussels.

The response to Canada’s new math from NATO and close allies appears to be lukewarm: officials say that what can and cannot be counted as defence spending is very well defined.