PEABODY – U.S. Rep. John F. Tierney on Friday challenged his eventual Republican adversary to a public debate.Tierney, a Salem Democrat, has sent out letters inviting the winner of the Sept. 14 Republican Sixth Congressional District primary election, either William Hudak of Danvers and Robert McCarthy of Saugus, to debate the issues. It marked the first formal debate invitation for the Nov. 2 general election, with Tierney emphasizing the importance of allowing voters to hear directly from the candidates.”John is looking forward to debating issues of importance, and providing voters with an opportunity to learn more about the differences between the candidates for Congress,” said spokesman Kathryn Prael. “While John continues to discuss with voters his efforts to create new jobs, strengthen our economy and protect Social Security and Medicare, the Republicans vying for their party’s nomination have voiced their support of the failed Bush policies of the past that left our country with an $11.5-trillion debt and sided with Wall Street CEOs instead of working families.”Prael said voters deserve the chance to hear directly from the candidates on these critical issues.In his letter of challenge to the two Republican candidates, Tierney wrote, “I believe strongly that the voters of the Sixth Congressional District deserve to have the issues debated by the candidates who seek to represent them. Despite the efforts of one of you, I am disappointed there has not been a debate before your Republican primary election. Vigorous debate is essential for the voters to understand the choices in this election.”Tierney said his campaign staff will contact the winner of the Republican primary to discuss specifics of the debate.