It's really honored to make an address to a foreign congress, especially in a foreign language. Japan's Prime Minister Shinzo Abe did it in the United States.
I was simply moved by the speech, not only his speech itself but also the effort of the officials in both countries. I don't have the right to judge his English, but you may understand the difficulty of the situation. Can you do that yourself?
You might say I'm naive, but I have to admit I was moved at the moment when former American soldier of Iwo To and a grandson of General Kuribayashi did a historical shake hands. It reminds me of the surrounding of the American Civil War. General Grant said, " The war is over. The rebels are our countrymen again." The Confederate troops were pardoned and they were even allowed to back home with their horses and arms.
Some people say he did not need to deliver a speech in English, but in Japanese. I don't think so. English has become the common language in the world. It's not simply native language in the United States.
If Japanese politicians have enough time for prepare for making speech in English and for practice the speech, they should do that as much as they can.