In case you missed it, the Washington Post has an excellent graphic laying out where each Representative and Senator stands on the AUMF for Syria. The Post has divided Congress into four categories: "Against military action", "Leans no", "Undecided", and "For military action". Long story short: this is a winnable fight for those of us out there who want Congress to say "No" to the war.
To break it down a little more, it looks almost certainly DOA in the House. There are 103 members who are definitely against, and 102 are in the "Leans no" category--a grand total of 205 negative votes right now. "Undecided" holds a plurality of the votes right now, with 143 Representatives in that category, but we don't even need anything close 50-50 split in this group if we can keep the "No" votes together.
The House is also fairly bipartisan in their opposition. 54 Democrats are currently among the 205 who are either certainly or leaning towards a "No" vote, and they also make up a large majority of the undecideds, with only 48 Republicans in that category. However, of the 24 in the House who do favor military action, exactly 2/3 are Democrats.
In the Senate, the picture isn't so rosy. "Undecided" holds a majority, with 53 Senators. The "Yes" and "No" columns are fairly evenly split. There are 14 definite "No" votes, and 10 who are leaning that way. Meanwhile, 23 Senators favor the strike. It looks like it's going to be a tough fight there, especially with Democrats in the majority.
The partisan breakdown in the Senate is roughly the same. Of the 24 who are in the "No" column (both leaners and definites), there are 5 Democrats and the Independent Bernie Sanders. Meanwhile, Democrats make up a majority of both the Undecided and "Yes" column.
Of course, if one house of Congress votes against this, the AUMF will be dead regardless. The House looks like it will be doing the right thing, but we need to keep up the heat on members in both houses, especially people represented by members in the "Undecided" and "Leans No" categories. Find your Representatives and Senators here.