Here is the petition - https://petitions.whitehouse.gov/...
With the new law made few months back - you cannot unlock your phones even if you are ready to pay the penalty to your provider. You cannot unlock your phones even after your contract has expired.
Unlocking the phone is not the same as rooting it.
In most countries GSM phones are sold separately in phone stores and not by Telcos. You buy a phone & you then chose your provider. You get into a contract with the telco provider (this can be prepaid or postpaid) but you can stop it at any time and move to a different provider with 0 penalty.
In the USA, Telcos sell you phone at subsidized rates, but hike up the monthly rates to cover it. They charge you a penalty if you don't stick with them for the term of the contract. But even if you still with them for the duration of the contract, you still cannot use the phone with a different network because they sold you the phone locked.
Unlocking a phone to use with a different provider is not difficult, but it was made illegal in 2012, Please sign the petition to make it legal again. Only 7000 more signatures are needed.
Once you have paid for the phone, it's your phone. You should be able to do whatever you want with this. This is yet another law paid for by the lobbyists.