U.S. Sen. Mary Landrieu’s flacks could have crowed and told the truth at the same time, but that proved too much of a strain.

While lies are only to be expected in their line of work, the real pros will try not to be too transparent. You could see through the Landrieu campaign’s latest whopper from a mile away.

It came in response to a clumsy GOP attempt to have Landrieu booted off the ballot in the upcoming election. A lawsuit designed to accomplish that went down in flames, providing the Landrieu campaign with a great opportunity to gloat and poke fun. But a gross and blatant misrepresentation of why the judge ruled in Landrieu’s favor diverted some of the attention away from Republican ineptitude.

State Rep. Paul Hollis, R-Covington, who recently abandoned plans to run against Landrieu, filed the lawsuit maintaining that she was not qualified to seek a fourth term because she doesn’t live in Louisiana, but in Washington, D.C.

The allegation that Landrieu has become a creature of the beltway, indifferent to the concerns of her constituents, is a recurring theme of the GOP campaign and one that could well cost her points in an election that promises to be a squeaker.

We will be hearing much more about what the lawsuit called her “$2.5 million residence on Capitol Hill.” Although the price tag is irrelevant to the residency question, Republicans never fail to mention it, evidently figuring it helps them portray her as out of touch with the po’ folk in Louisiana.

Filing the lawsuit, however, was a dumb move, because no more than a rudimentary grasp of the law was required to see that it was bound to fail. But when it did, the Landrieu campaign was not content to welcome the decision and mock Republicans for screwing up. There was plenty of scope for that.

Instead, the campaign declared, “The judge was clear — Sen. Landrieu resides in Louisiana and is qualified to run for the Senate.” Not true.

State judge Wilson Fields was indeed clear, but he threw the suit out without even addressing the question of where Landrieu resides. The U.S. Constitution requires that a senator “when elected, be an Inhabitant of the State for which he shall be chosen.” What matters is where a candidate lives on election day, Fields ruled. Hollis and his attorney Matthew Monson had jumped the gun, so case closed and no need to address the claims made in the suit.

Fields would have been entitled to ignore the lawsuit altogether, because it was filed a couple of minutes too late. Monson blamed a busy fax machine for that, and claimed that the state law that sets the deadline is unclear anyway. No it isn’t. It says that a suit must be filed “ no later than 4:30 p.m. of the seventh day after the close of qualification.”

That was not Monson’s only elementary mistake. When the suit was filed, it said Landrieu lived in Orleans Parish when its entire burden was that she didn’t. Monson blamed clerical error — it should have said she “claimed” to live -— but the attorney whose name is on the suit is generally expected to know what is in it.

This was clearly amateur hour. In the course of a brief hearing before Fields threw out the suit, Monson attempted to explain that Landrieu should be barred from running, because, although she has a “residence” in New Orleans, it does not qualify as her “domicile.” When Fields asked for a legal definition of “domicile,” Monson confessed, “I actually don’t know.” This lawsuit deserved not to be simply dismissed, but to be laughed out of court. Fields thought it so frivolous that he ordered Hollis pay all costs.

In fact, state law says that a candidate may have several residences, the “habitual” one being his or her domicile. The New Orleans address where Landrieu is registered to vote is a house she partly owns and where her parents live.

Maintaining a Washington pad is hardly to be counted a vice in a member of Congress, but whether Landrieu qualifies as an “inhabitant” of Louisiana is a question that cannot be raised in court unless she is re-elected first.

If that happens, it is hard to imagine that the courts will negate the will of the people on the strength of distinctions between residence and domicile that are too abstruse for most voters to understand without consulting an attorney. Clearly there is a danger they wouldn’t understand even then.

James Gill’s email address is jgill@theadvocate.com.