Defense Secretary Gilbert Teodoro was thrown a startling question last week which had to do with the US coming to our defense.

Asked at a news conference in Australia if he expected incoming US president Donald Trump to demand that we pay for US protection, Teodoro replied: “I really don’t expect some sort of a statement from Mr. Trump, hopefully not.”

Considering that the “ironclad” Philippine-US alliance seemingly comes at no money cost to us, you might be bewildered over why the question was raised.

Initially, we can view the question as an instance of the jitters surrounding Trump’s return, where many expect dramatic shifts in US foreign policy for which we must brace ourselves as our senators are demanding.

But, in the ugly scenario that Trump suddenly issues a crazy Tweet casting serious doubt on US defense commitments to us, it is high time we were properly informed about where mercurial Trump might be coming from.

Firstly, it helps that the question asked of Teodoro alludes to two foreign policy buzzwords making the rounds of the incoming “hawkish” Trump 2.0 regime: “transactional Trump” and “free ride.”

Knowing first what “free ride” means will readily explain the question, while “transactional Trump” in turn tells us why Trump bristles over “free ride.”

Essentially, “free ride” is a euphemism for Trump’s frequently depicting US allies worldwide as freeloaders sponging on US military aid when dealing with geopolitical threats.

Now, in our part of the world, Trump’s “free ride” grievance isn’t really directed at us but mainly toward two major US allies — Japan and South Korea.

In Trump’s first term, he reportedly demanded a five-fold increase in what South Korea paid toward the cost of stationing US forces there. Other reports said Trump wanted a similar increase from Japan to support the cost of basing US troops there.

Trump is likely to make the same demands, even if the two countries have been ramping up their defense spending in recent years and have started considering building their own nuclear weapons to lessen their dependence on the US nuclear umbrella.

But why would Trump even raise such demands on allies, who like us face a shared threat from China?

Well, it has a lot to do with Trump’s transactional approach to foreign policy.

As one strategy paper puts it: “His (Trump’s) campaign statements underscore a fundamentally transactional mindset, whereby he subordinates most other objectives — strengthening US alliances and partnerships in Asia — to that of creating what he sees as a more balanced economic relationship with Beijing.”

This means deal-making “businessman” Trump views the US-China rivalry more about negotiating economic relations than any other geostrategic concerns.

In short, Trump views everything through the lens of trade than, let’s say, outright war. Trump, in fact, openly admits it is easier to win a trade war than actual hostilities.

The point, therefore, is that the biggest foreign policy issue to watch out for is how US-China economic relations evolve once Trump is back in the White House.

How it will evolve at first will likely involve Trump trying to inflict more pain on China’s already weak economy by imposing a tariff of at least 60 percent on Chinese exports. Other US trading partners face tariffs of 10 to 20 percent on their exports.

Our trade with the US, of course, is vital to us. But Trump’s potential dealmaking with China has critical implications for our difficulties with China’s aggressive posturing in the WPS. It also prevents nasty surprises down the road.

If, for instance, tensions between us and China lead to an imminent threat of armed conflict, Trump, as one study noted, “is likely to personally intervene and conduct summit diplomacy with President Xi Jinping to seek a transactional solution. Trump will be inclined to seek a quid pro quo with China over the head of the Philippines.”

Trump bargaining us away without us even knowing is never in our best interest.