Sen. Mary Landrieu has been doin’ work over the past couple of weeks to portray herself as pretty much the One True Champion of the Keystone XL pipeline; it goes without saying that her fellow Democrats who remain opposed are feckless Obama rubber-stampers on the matter (not like her, you see — she’s willing to personally take the president to task), while Republicans, she contends, are merely out to exploit the pipeline’s popularity as an election issue through which they can rage about Obama’s anti-jobs agenda clear through November. I’m sure Landrieu wouldn’t know anything about that kind of attitude, ahem — but whatever the case, consider the latest polling from Southern Media & Opinion Research. Ouch:

Senator Landrieu’s job performance rating continues to deteriorate. Her positive ratings have dropped to an all-time low of 39% in this current poll. Her negative ratings have increased by 30 percentage points in a little over a year and a half (from 28% in September 2012 to 58% in this current poll). …

While the intensity of likely Louisiana voters giving Senator Landrieu a rating of “excellent” has varied little since September 2012 (12% in 2012 and 15% in the current poll), the intensity of those voters rating her job performance as “poor” has tripled (from 13% in 2012 to 39% in the current poll). …

Senator Mary Landrieu draws 36% (down from 41% last fall) of the vote in a four-way trial heat with Republican challengers Bill Cassidy, Paul Hollis and Rob Maness who collectively draw 46% (35% Cassidy, 4% Hollis and 7% Maness) of the vote; of the remaining, 17% are undecided and 1% refused to say.