Loyalty, in the opinion of Rep. Martin Frost (D-Tex.), ought to be a two-way street.

So when he saw a news report earlier this week that former representative Yvonne Brathwaite Burke of California had convened the first meeting of the Democratic Party commission on "platform accountability," Frost fired off a letter to party Chairman Charles T. Manatt.

It is "rather ironic," Frost said, for Burke to be devising ways to "discipline boll weevil Democrats" and others "who have not been loyal to the Democratic Party . . . in light of the fact she recently made a campaign appearance in Dallas on behalf of my Republican opponent."

Frost, an ally of Majority Leader James C. Wright Jr. (D-Tex.) and an enforcer of discipline himself in the House whip organization, sent Manatt a copy of a brochure Lucy Patterson, his GOP opponent, is using, showing herself with Burke.

The story is a bit complicated. Patterson, a former Dallas councilwoman, filed against Frost in the Democratic primary after redistricting raised the percentage of black voters to almost half.

When Burke came in as the featured speaker at a $50-a-head Patterson fund-raiser Jan. 30, there was speculation that Patterson would eventually run as a Republican. On March 12, she dropped out of the Democratic primary and accepted the GOP nomination.

Burke said last night that Patterson was running as a Democrat when she endorsed her, and "if she is now a Republican, she knows I cannot support her."

As for Frost's charge of disloyalty, Burke said, "There's nothing in the party rules that says you cannot endorse another Democrat against an incumbent." She said many black elected officials were supporting Patterson against Frost, who is white.

Frost said that the moral of the story was an old one: "People who live in glass houses had best be most careful when throwing stones."