In this week's story about a possible challenge next year to House Speaker Frank Chopp, I wrote:

Progressives have tried to knock off a moderate-leaning incumbent from Seattle before. In 2004, labor unions targeted pro-choice Democrat Helen Sommers in the primary because she failed to halt corporate tax breaks and opposed raising pay for home health-care workers. The challenge fell short; Sommers was easily reelected.

Seeing this, a local labor leader wrote me to point out that while the 2004 challenge did indeed fall short (in the primary), and Sommers was easily reelected (in the general), a closer look at that year's primary results is useful.

In that 2004 primary, labor's candidate, Alice Woldt, very nearly beat Sommers, earning 48.4 percent of the vote to Sommers' 51.6 percent.

This was back before the top-two primary allowed members of the same party to run against each other in the general, so in November of 2004, with Woldt out of the picture, Sommers stomped all over her Republican and Libertarian opponents, earning nearly 79 percent of the vote and easily retaining her seat.

But the key thing to note here is that this was before the top-two primary. If labor's primary challenge to Sommers had taken place this year, she'd have been in the general election with a "surging" Woldt, and it would have been much tougher for her to hang on to her spot in the house.

In other words, the lesson of the challenge against Sommers, applied to today's election rules, cuts both ways. Yes, it's still hard for a Democratic challenger to take down a well-known Democratic incumbent. But thanks to the top-two primary, it's also easier than ever before.

Get into the debate over whether, as commenter West Seattle Walter says...

Frank Chopp will not lose.

...HERE.