When Rep. Bill Cassidy recently issued a news release touting his strong fundraising performance in the first quarter of the year, the Baton Rouge Republican said it “puts my campaign in an extremely strong position.”

It came as no surprise to political activists that he didn’t say “my campaign for re-election.” One of the worst-kept secrets in politics has been that Cassidy planned to challenge Sen. Mary Landrieu, D-La., in next year’s election. Cassidy made that official last week, releasing an announcement video.

If the campaign’s fundraising has been successful, Cassidy is surely correct that he faces a tough campaign ahead — and, quite possibly, not just against Landrieu.

Some Washington insiders had questioned why Cassidy had not announced earlier, saying that avoiding an official announcement would encourage other Republicans to enter the race.

Others mentioned as potential candidates in the Senate race are former Rep. Jeff Landry, R-New Iberia, as well as Chas Roemer of Baton Rouge, president of the state Board of Elementary and Secondary Education.

Rep. John Fleming, R-Minden, took himself out of consideration, as have some other prominent GOP figures.

However, as Washington insiders apparently are unaware, the idea that the Republican Party can “clear the field” of other challengers is not easy to achieve in Louisiana.

In most states, a Republican-only primary is held to determine a Senate nominee, who then faces off the winner of the similar Democratic primary election.

Our system of open elections, in which anybody can qualify for a modest filing fee, works against clearing the field.

That doesn’t mean that Cassidy won’t be the major GOP candidate against Landrieu, and an early announcement — the primary is in November 2014 — is one way to achieve that end, by seeking a head start in organizing and raising money.

Even if achieved, Cassidy’s first goal is only part of the way, because Landrieu has shown herself to be a tough competitor, winning three terms in the Senate. With a particularly significant legislative accomplishment recently — dedication of BP oil leak fines to the Gulf Coast — and a strong track record in bringing home the bacon, she will be a tough candidate to beat, even if Louisiana has been trending Republican in recent years.

For Cassidy, strong points include a base in populous Baton Rouge and the recent addition to his district of some parishes down Bayou Lafourche, where he has been working to make himself better known.

This an interesting pairing, whether others jump into the race, or not.