[derivativethrow]

No, material and nonpublic is necessary but insufficient for the trading to be illegal. It must also break a confidentiality agreement, fiduciary duty or specific law pertaining to the way the information is released to the person and their duties thereof.

This is to say that it's illegal for congresspeople to trade on material, nonpublic information because there is now a law explicitly governing it. If they (or anyone) develop the material, nonpublic information through original research, it's not illegal.

Don't trust Wikipedia summaries for these things.

[albntomat0]

Do you have a good source to recommend with a more detailed overview?

[derivativethrow]

Read the SEC documentation on insider trading directly. Barring that, Matt Levine gives accessible (and entertaining) which is informative for a lay audience.