Foreign Affairs Minister Stéphane Dion blocked a shipment of military goods to Thailand this year, with his department citing human rights among the reasons. Only months earlier, the Liberals approved the lion's share of a $15-billion export of combat vehicles to Saudi Arabia – a country regularly excoriated for its human-rights record.

The stark contrast in how the Trudeau government treated arms shipments to the two countries surprised rights advocates and weapons-trade experts, because Saudi Arabia gets poorer marks on human rights than Thailand, at least by some benchmarks.

U.S. liberty watchdog Freedom House, for instance, gave Saudi Arabia its worst rating – 7 out of 7 – on all three benchmarks in a 2016 report: political rights, civil rights and an overall freedom rating. By comparison, it gave Thailand 6 out of 7 for political rights and 5 out of 7 for civil rights and an overall freedom rating of 5.5.

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The Canadian government earlier this year declined to reveal whether it blocked or allowed these military exports to Thailand, saying to divulge this could hurt the company that was trying to ship them. On the two projects, officials asked Mr. Dion to render a "ministerial decision" due to their sensitive nature.

The Globe and Mail obtained records through Access to Information law that show Mr. Dion decided on Aug. 2 to block the military-goods shipment to Thailand, accepting a recommendation from his department. The Department of Global Affairs still refuses to reveal the nature of the military goods – citing the need to protect the would-be shipper – but a spokesman said the number of items was "modest."

Size, it turns out, is a major difference between these two cases. The sale of combat vehicles to Saudi Arabia is the largest advanced manufacturing export in Canadian history, and defenders declared it necessary to sustain thousands of jobs in Canada.

The thumbs-down for Thailand came four months after Mr. Dion approved permits in April covering more than 70 per cent of the $15-billion sale of weaponized armoured vehicles to Riyadh.

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A spokesman for Mr. Dion's department declined to explain why the exports to Thailand were rejected when the Saudi deal got the green light. John Babcock would say only that these are case-by-case decisions and the minister made this one "based on foreign-policy and human-rights considerations." Mr. Babcock said decisions follow "an analysis of whether the equipment or technology is likely be used to commit human-rights violations and whether the export is consistent with Canada's foreign and defence policies."

Alex Neve, Amnesty International Canada's secretary-general, said the fact that the government makes such decisions on arms exports behind closed doors – without releasing deliberations – makes it hard to sustain faith in Ottawa's ability to police military sales to foreign countries.

"When situations like this come along [in which] the inconsistency between two decisions seems so glaringly apparent … it erodes confidence in the system."

He called for more transparency. "In order to have confidence that our arms-control system is reliable and has integrity, we need to be sure there is consistency across all situations and that it's human-rights considerations that are at the fore – not political, economic, geostrategic or other factors."

Documents show that in recommending rejection of the Thai deal, Global Affairs reminded Mr. Dion that Canada condemned the 2014 coup and restricted "military and high-level engagement" with the Thais. "Although the junta had initially pledged to restore democracy and hold elections by early 2016, the date has now been pushed back to summer 2017 at the earliest." The department noted the junta has restricted freedom of the press, prevented public gatherings and imprisoned citizens for criticism. Before the coup, an army crackdown wounded more than 1,000 protesters and killed 90.

Saudi Arabia is an absolute monarchy with a long history as a human-rights offender for its treatment of women and dissidents. It faces allegations from a United Nations panel of violating humanitarian law during a bombing campaign in Yemen that is blamed for the deaths of thousands of civilians. It also faces accusations of funding extremists and terrorist groups. This year, it carried out a mass execution of 47 people, including prominent cleric Nimr al-Nimr, an outspoken critic of the House of Saud.