**Yes**, you can wear it.

>Search Results For:
>
>**lapel pins**
>
>You may transport this item in carry-on or checked baggage.

Source: [MyTSA][1]


I do not believe there is any need to pack it into check-in luggage. Just like any other metal items on you, for example a belt buckle, you can take the pin off the jacket and put it in the tray with your other items while you cross the security screening gate.

>**What can I do to prevent an alarm?**
>
>To reduce the likelihood of an alarm that results in pat-down screening, remember to remove all items from your pockets before you go through screening. You should avoid wearing clothes, shoes and jewelry with a high metal content.

**[TSA][2]**

Specially that the lapel pin is not a prohibited item as declared by TSA. Safety Pins, Bobby Pins and Stick Pins are all allowed both in checked bags and carry on bags. I'm sure a clothing item allowed in carry on bag is also allowed to be worn, even though its best to put it on the belt to avoid triggering the alarm.

**[TSA: What Can I bring?][3]**


  [1]: https://apps.tsa.dhs.gov/mytsa/cib_results.aspx?search=lapel%20pin
  [2]: https://www.tsa.gov/travel/frequently-asked-questions
  [3]: https://www.tsa.gov/travel/security-screening/whatcanibring/printable