A more people learned latin
The correct answer to this open question is the following.
The power of Congress that Senator Paul probably most concerned about based on this passage is the Power to Declare War.
The United States Constitution states on Article I, section clause 1, that the United States Congress has the power to declare war. The Constitution grants Congress with expressed powers and this is one of them. That is why Senator Rand Paul is reflecting on the great responsibility Congress has regarding thus power of declaring war against another nation.
Dear Grand Daughter
I don't know if I will still be there when you get a chance to read this letter.
Things must have changed a lot by the time you read this.
I am an old man already, and belong to a different time. In our era, large and extended families loved together and loved each other. However, I already see large families breaking up and everyone being very individualistic, something I detest.
However, I have seen some amazing changes take place in front of me. I saw the development and growth of Radio, Telephone, Airplanes, Movies and TV! And I can't imagine the things you would see in your time.
Just remember one thing my love, change is the only constant in life. Never feel bad about it! Embrace it and you will be successful, if you avoid it, you will only Perish
I hope you find this letter in a time and place where you feel the happiest and I only wish the best for you
Yours truly
Your Grand dad