Sen. Jean Carnahan, the Missouri widow appointed to the Senate after her husband died in a plane crash, will run for the seat this year.

The news was no surprise; even before taking the oath of office, Mrs. Carnahan, a Democrat, said she would seek to finish the six-year term if she felt she was accomplishing something. And she raised more than $2.3 million in campaign money before the year was half finished.

"I'll be making a formal announcement in the coming weeks," Mrs. Carnahan, 68, wrote supporters in a letter released Tuesday, "but I wanted you to know today that I will run for the U.S. Senate because I feel I am making an important difference for Missouri."

Appointed to serve after voters chose her late husband, Gov. Mel Carnahan, over incumbent Sen. John Ashcroft, Mrs. Carnahan must run for election in November in order to retain the seat. She is likely to face Republican Jim Talent, 44, a former congressman from St. Louis who lost the race for governor to Democrat Bob Holden by about 21,000 votes.

In the two-page letter, Mrs. Carnahan emphasized her work on the Senate Armed Services Committee and her support for more military spending to strengthen U.S. national defense and battle terrorism.

She also mentioned joining with a handful of moderate senators who shaped a compromise on President Bush's tax-cut plan. The centrists helped shave the total size of the reduction and increase the share going to low- and moderate-income people.

She mentioned congressional action involving Missouri, from airline and aerospace interests to federal spending projects and help for struggling farmers. She also told supporters she is proud of adding measures proposed by her late husband to an education bill signed into law recently by President Bush.