Protectionist trade policies are often enacted with the political intention of strengthening exports, and hence GDP. Examples

Question:

Protectionist trade policies are often enacted with the political intention of strengthening exports, and hence GDP. Examples of protectionist trade policies include quotas and import taxes.
What is the impact of the protectionist trade policy on the real (assume we are using the US an as example, and the US has enacted some protectionist policies)?
Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...