After three terms of service, Senator Mary Landrieu was defeated in the December runoff 56-44%. While pundits attributed her defeat to the unpopularity of President Obama in Louisiana, the seeds of her defeat were sown long before that.

Senator Landrieu’s fundamental problem was that she had a low ceiling of support – in the three election cycles (1996, 2002, and 2008) she was on the ballot before 2014, she never received more than 52% of the vote. And a closer examination of her 2008 vote revealed she was on shaky grounds even before Barack Obama was inaugurated as President in 2009.

If we were to go back to Senator Landrieu’s 2002 runoff victory, we see that the electorate in that year was 71-27% white/black. While she received a near unanimous black vote, she also received only 36% of the white vote.

Between her 2002 and 2008 re-elections, two events when combined gave her an electoral lift that was her 2008 margin of victory: (1) 2008 was a Presidential election year, which meant increased (and more Democratic friendly) turnout. Plus, with Barack Obama also on the ballot, black turnout surged from 27 to 30% of the electorate, and that 3% change in the electorate also helped the Landrieu campaign, (2) in the parishes in Metro New Orleans that saw the most damage from Hurricane Katrina, her performance improved from 56-44 to 59-39%.

Despite the electoral benefit she received from these two extraordinary events, her re-election percentage was the same 52% of the vote that it was in 2002. However, her share of the white vote fell from 36 to 34%, and in 39 of the state’s 64 parishes, her share of the vote fell from 50 to 47%.

Once Obama was inaugurated in January 2009, he (with the assistance of large Democratic majorities in both houses of Congress) pushed through a liberal agenda, and the resulting unpopularity also cast a negative shadow on Senator Landrieu. While her deciding vote for the Affordable Care Act (popularly known as “Obamacare”) became a mark on her record, her voting record on abortion and on gun control was also subject to scrutiny and was used against her. It didn’t help that the only demonstrably “conservative vote” that she could use in her defense was her failed attempt to get the Senate to approve the Keystone pipeline, and that attempt occurred during the runoff – nearly five years after which voters had already formed an opinion (pro or con) of her.

So it was her perilous electoral position, combined with her association with an unpopular Democratic President, which ultimately was her undoing. As much as commentators focused on her (successful) efforts to get a healthy black voter turnout, the fact remains that her share of the white vote was already trending downwards even before Barack Obama was inaugurated: that percentage was 36% in 2002 and 34% in 2008. In the primary, that number plunged to 21%, and only notched up to 22% in the runoff. In other words, her standing with white voters was not one where a winning coalition was possible to be built.

And it was her disastrous showing among white voters was the tale of the 2014 race. While the conventional wisdom was that the Democratic base was demoralized and wasn’t going to show up in the runoff, the reality was noticeably different – black turnout “spiked” in both the 2014 primary and runoff. Typically, the black vote is 25-27% of the electorate in a midterm type race. This year, however, the primary electorate was 68-29% white/black, while the composition of those voting in the runoff was 67-30% white/black. These are percentages you would expect to see in a Presidential election: in fact, the only other times the black percentages were ever that high were the two times (2008 and 2012) that Barack Obama was on the ballot.

In closing, a graphical depiction of the runoff vote by parish is below.

2014 Senate runoff by parish