After the 2004 general election, Rep. Meg Burton Cahill put together what she calls a “coffee table book” of campaign materials used against her in last year’s races for the House in District 17.

“There was a lot of hateful stuff done,” said the Democrat, who is now contemplating a campaign for the Senate next year to hold down Sen. Harry Mitchell’s seat for the minority party. Mr. Mitchell, assistant Democrat leader, is termed out in 2006 and is seeking the chairmanship of the Arizona Democratic Party.

After what The Arizona Republic described as a nasty series of back-and-forth attack mailers between her and Republican Laura Knaperek, Ms. Burton Cahill led all candidates with 26.8 percent of the vote in last year’s House race, which also elected Ms. Knaperek with 24.6 percent.

Then-incumbent Republican Mark Thompson was last in the five-way race in a district that voted 54.9 percent Democrat to 44.3 percent Republican.

Now, Mr. Thompson has filed for Mr. Mitchell’s seat, setting up — should Ms. Burton Cahill decide to file — a possible general election rematch in 2006, this time for the Senate. She says she will make a decision by the end of September.

“It would be easier to run for the House,” Ms. Burton Cahill said, adding that she feels it might be her “duty” to try to hold the Senate seat for Democrats.

Ms. Burton Cahill recently returned from the month-long Senior Executives in State and Local Government Program at Harvard University, where she said she was told that political races across the country are going to get more challenging.

“There’s an incredible political landscape down at the Capitol,” she said. —