Echoing a theme used by GOP presidential nominee Sen. John McCain (Ariz.) at the Republican National Convention earlier this month, 3rd district Democratic nominee Bob Lord says in his first TV ad that principle should always come before allegiance to one’s political party.

Lord, an attorney, is running to unseat Rep. John Shadegg (R) in the Republican-leaning, suburban Phoenix district. Earlier this year, Shadegg announced he would retire before changing his mind and deciding that he would seek an eighth term after all.

“John Shadegg actually says he puts his duty to support his party above everything else,” a voice-over says as the 30-second spot opens.

“This idea of putting party over principle is exactly what frustrates people about Washington,” Lord says as the ad closes. “Arizona deserves a Congressman who puts principle before party.

Lord’s ad, which is running on broadcast and cable, uses news reports to back up its claim that Shadegg supports party over principle. The National Republican Congressional Committee dismissed the spot as demonstrably false.

“If Bob Lord’s strategy is going to consist of making false and desperate claims about John Shadegg’s record as a reformer, then he is going to be laughed out of Arizona,” NRCC spokesman Ken Spain said.