Sen. Mary Landrieu's (D-La.) reelection bid has been in trouble for a long time. It was in trouble before the Nov. 4 election, when polls showed her likely to lose a head-to-head match-up against Rep. Bill Cassidy (R). It was in trouble after that election, when she performed worse than polling predicted and when her weird, long-shot strategy of getting approval for the Keystone XL pipeline failed completely. And it is in trouble now for many reasons, not the least of which is the most important: The people who have already voted in the race are more heavily the sorts of people likely to vote against her.

The National Journal offered an overview of the early voting problem this morning, pointing out that the vote from Republicans was higher than in November, and the vote from Democrats lower. And back then, GOP candidates combined for 56 percent of the  vote, and Democrats 43.

It's perhaps easier to understand when visualized.

This graph compares the composition of the early voter pool at the end of the November election and as of Monday in the runoff. Gray dots are how Landrieu performed with the group in exit polls. Light-colored dots show the percentage of all early voters in November that were from the demographic group; dark-colored dots, the composition now. The arrows show how things have changed.

More early voters are male, white, and Republican -- groups that voted for Cassidy at 48, 59 and 73 percent, respectively, according to exit polls. Fewer early voters are female, black  and Democratic -- groups that voted for Landrieu at 48, 94 and 86 percent, respectively. Landrieu was the top vote-getter last month, but barely.

We added another data point in the party composition figures. The very light-colored dots show the composition of the early vote about a week before Election Day last month. The percentage of the vote that was Republican actually increased slightly over the last week in November and the percentage that was Democratic dropped. If that holds for this election, it means that Landrieu's numbers would get even worse.

This is all speculative. Early voters don't always hew to what happened in the past and, of course, there are fewer candidates on the ballot (two, to be precise). But when fewer of the early voters are from Landrieu's strongest constituencies, it's not the sort of thing that should make her feel more confident about her already precarious position.