Update | 3:40 p.m. Alexi Giannoulias' campaign says it was him, not Kirk, who set the standard for releasing tax returns.
"We are pleased that after 10 years in office, Congressman Kirk has finally given in and made his tax returns available, though his refusal to release them widely remains a concern."
Spokeswman Matt McGrath added: "Alexi has released his tax returns for all the years he's been in office and will release all future tax returns when he files them. As he has done every year, he has filed an extension."
The campaign did not immediately explain why Giannoulias files for extensions.
Original post: Republican U.S. Senate candidate Mark Kirk today made his 2009 tax return available to journalists, challenging Democratic rival Alexi Giannoulias to do the same.
In March, Kirk made available previous tax returns dating back to 1999.
"To provide the people of Illinois with full transparency," said spokeswoman Kirsten Kukowski, "we hope Mr. Giannoulias will follow Congressman Kirk’s example and make his 2009 tax return available as well."
Giannoulias' campaign spokespeople did not immediately respond to requests for comment on whether their candidate planned to release his returns.
According to The Associated Press, the returns show that he made nearly $160,000 last year and paid more than $32,000 in federal taxes.
Kirk's returns are not available electronically. To view them, media must visit campaign headquarters or arrange a meeting with staff. Those who view the documents are not allowed to make copies.
"We kind of established the ground rules coming into this," Kukowski told me. "I don't think that we're standing in the way."
Here's Kirk talking taxes on everyone's favorite day of the year.