It is reminiscent of the quandary faced by Gen. Maurice Gamelin on the evening of May 15, 1940. Suddenly he realized that German panzer troops had broken through the supposedly impassable Ardennes.
French troops to the north were cut off and rendered useless, troops to the south were falling back in disarray on all sides and no reserves were available between the front and Paris. "Yes," he told the prime minister, "it means the destruction of the French Army."
Now, analogies between military history and politics are never exact, and no one in American politics remotely resembles the Nazis. But there is some resemblance between the plight of Gen. Gamelin and the plight of Democratic strategists in key Senate and congressional races this year.
The general had run out of feasible alternatives. His one hope was that the other side would make a mistake. Alas, the Germans didn't, and a great nation was lost within a few days.
Today's Democrats face losing an election, not a nation, and the cause is Obamacare. They stand on ground of their own choosing, which they suddenly find themselves unable to defend, and they must hope that the opposition makes disabling mistakes.
That has been made starkly clear by Republican David Jolly's defeat of the better-known Democrat Alex Sink in the Florida-13 special election on March 11. The margin wasn't large, 49 percent to 47 percent, and the dropoff in Democratic vote not huge -- President Obama carried the district 50 percent to 49 percent in 2012.
What was more significant is that the well-financed, national party-selected Sink was unable to defend her ground.
Entirely missing from her campaign was a message along the lines of "hands off my Obamacare." You would have heard something like that if a Republican had advocated repealing Social Security or Medicare a year or two after these programs were passed.
But support for Obamacare has been under 50 percent since before it was passed. Democrats would be running ads showing happy Obamacare consumers if they could find any.
Instead they are fending off backlash from ads showing ordinary people who have lost the coverage they had and wanted to keep. Their spokesmen are getting into arguments with cancer patients -- arguments they can't really win.
The Sink campaign, blessed with a non-incumbent candidate who didn't actually vote for Obamacare, tried the national party's recommended "fix it" stance. As maverick blogger Mickey Kaus has pointed out, Sink's suggested fixes were thin gruel, but he suggests others that might be more attractive.
Some polls show "fix it" to be as popular as "repeal." But Republicans, including Jolly, have already been maneuvering around that, as the panzers maneuvered through the Ardennes, by coming out for "repeal and replace."
And congressional Republicans have come forward with intellectually serious and probably politically appealing "repeal and replace" alternatives.
Another alternative for a campaign on the defensive is to change the subject. But the Sink campaign did not see fit to stress themes the president has been voicing, addressing "income inequality" by raising the minimum wage or increasing overtime pay.
Those policies get wide approval in polls. But there's little evidence that they're important enough to voters to swing votes.
Instead, the Sink campaign trotted out traditional Democratic themes. Republicans would "privatize" Social Security. They would threaten Medicare.
But "hands off Social Security and Medicare" doesn't seem capable of gaining ground, even in Florida-13 with its large elderly population.
In 2012, Democrats hammered Rep. Paul Ryan's plans for Social Security. But by bringing the issue out in the open, they allowed Ryan to make clear, as his invariable first point, that he would change nothing for anyone over 55. Grandma remained unscarred.
On Medicare, it's not the Republicans but the Democrats who are cutting -- as part of Obamacare -- funding for Medicare Advantage plans. That may not scare Grandma, but it's not likely to make her vote Democratic. The Romney-Ryan ticket carried Florida's elderly.
Looking ahead, Democratic incumbents and candidates in seven states carried by Mitt Romney are running under 50 percent in polls. That's true also of Democrats in four 2012 presidential target states carried by Obama.
Obamacare leaves those Democrats in a position that resembles Gamelin's: They have no good alternatives.
Except to hope for mistakes by Republicans -- who have shown quite capable of mistakes in the past. We'll see how many they make this time.