The following is from an article in the New York Times: What Congressmen Are Hiding
It’s sobering to recall that the 1995 law was passed three years after another congressional scandal, in which House members of both parties were censured and prosecuted for abusing accounts with the House bank, in some cases writing checks for tens of thousands of dollars they didn’t have. The same environment of entitlement, secrecy and lax rules led to the current situation.
Some dictionaries define 'sobering' 'making you think about things in a serious way' but after seeing the synonym of 'sobering' as 'depressing, discouraging, daunting, saddening, dispiriting, disheartening' I am not so sure of my understanding.
I feel the definition seem to fit better, but I am not sure because the synonyms, especially 'saddening' or 'disheartening' seems to work in the context as well. The writer is disgusted that politicians made a bad law when they had a chance to make a better one.