system
Given the following post, respond as if you're commenting on Reddit:
human
I want to understand Trump’s “trade war” on allies better

When I heard he was imposing tariffs on allies, such as Canada, I immediately just assumed that it was dumb. Then I heard they tariffs on us first and were asked to stop before Trump did what he did but that was from someone that doesn’t know the situation that well. So my question is were they tariffing us first? And if they were why? How long? And on what?

Edit: thank you to everyone that has responded, I think I get it now but if there is anything that you feel was messed please go ahead and explain it.
gpt
**1. The tariffs are nothing new.**

The tariffs have been around for decades, well before NAFTA. The USA aren't reacting to any new development. As such, if Trump wanted Canada to drop dairy tariffs, that could have been on the agenda when renegotiating NAFTA.

**2. The tariffs are on dairy products.**

Within NAFTA or any other free trade agreement, not all goods are duty-free. Each country sets a list of exceptions and that list is the source of much of the negotiations. 

The sole example brought by Trump so far is dairy products.  

**3. Supply management is the cause.**

Canada imposes the tariffs on dairy because of supply management, which has been in place since the 70s. The result is that the supply of milk becomes severely limited and that drives dairy prices up. The intent was create more stability for dairy farmers.

On the flip side, it makes Canadian milk dar more expansive than foreign milk. The system would crumble apart without protectionism.

**4. That wasn't the inital justification given.**

The US initially claimed tariffs on steel and aliminum were due to "national security." When Canada pointed out how preposterous it was deem Canada, America's closest and steadfast ally, a threat to national security, Trump then claimed it was due to dairy tariffs.

**5. Canada imposes these tariffs on everyone.**

During the CETA negotiations with the EU, a major sticking point was by how much to increase the quotas on foreign cheese. In other to protect its cheesemakers working with costlier milk, Canada limits duty-free cheese imports. As such, French cheese are more expansive in Canada than the US due to smaller supply.