What does “wears his opposition to trade deals as a badge of pride” mean?

Question

Bernie Sanders, the rival to Hillary Clinton, the presumptive Democratic candidate, wears his opposition to trade deals as a badge of pride.

I don't know what are "wear his opposition", "trade deals" and "badge of pride".

The context is:

The anxieties that such findings stoke have made trade a touchstone issue in America’s presidential election. Donald Trump, the Republican front-runner, promises to slap prohibitive tariffs on imports from China and Mexico. Bernie Sanders, the rival to Hillary Clinton, the presumptive Democratic candidate, wears his opposition to trade deals as a badge of pride.

_{Source: The case for free trade is overwhelming. But the losers need more help | The Economist}

Answer 1

"Wears ____ as a badge of pride/honor" is a set English phrase that means

something that represents or is a sign of something else
He wore his ethnic heritage as a badge of honor/pride. [=he was proud of his ethnic heritage and did not try to hide it]

So, in this example, Bernie Sanders opposes trade deals and is proud of the fact and maybe even brags about it.

"Trade deals" is referring to his opposition of many of the different trade agreements that have come through Congress in the time he's been in office.

A trade agreement (also known as trade pact) is a wide ranging tax, tariff and trade treaty that often includes investment guarantees. The most common trade agreements are of the preferential and free trade types are concluded in order to reduce (or eliminate) tariffs, quotas and other trade restrictions on items traded between the signatories.

Bernie Sanders is well known for disliking free trade agreements. This site has some examples of quotes from Sanders about his opinions on trade deals.