Kay Bailey Hutchison is leaving the U.S. Senate and with her departure, the spirit of bipartisan cooperation on Capitol Hill has taken another punch in the gut.

Hutchison is a Texas Republican who counts among her better Senate friends any number of those dreaded Democratic Senate liberals. Barbara Mikulski of Maryland comes to mind. She worked with Hutchison to craft women-friendly legislation during the time they served together in the Senate.

Hutchison’s bipartisan chops go back even prior to when she was first elected to the Senate in 1993, when she succeeded the late great Lloyd Bentsen, a Democrat who was selected to become Treasury secretary in the Clinton administration.

Hutchison ran for Texas treasurer in 1990 when the late Democrat Ann Richards vacated the office to run for governor that year. I asked Hutchison during that election year what she would do differently in the treasurer’s office. Her answer surprised me. Richards ran the office so well, Kay said, that she didn’t want to change a thing.

I’m trying to imagine one of today’s Republicans – those who are influenced by the tea party wing of their outfit – saying something like that. I can’t get there.

Capitol Hill’s bipartisan spirit has been broken with each departure, particularly among the Republicans who used to run things in DC. Olympia Snowe of Maine? Gone, citing the bitterness that has infected Washington. Dick Lugar of Indiana? Also gone, the victim of a GOP primary loss to tea party favorite Richard Mourdock, who then lost the general election after declaring it is “God’s will” when a women becomes pregnant as a result of a rape.

And now, Kay Bailey Hutchison is leaving. Hutchison announced her intention to leave the Senate only to lose her Texas governor’s primary challenge of incumbent Rick Perry, who did a masterful job of demonizing her as a creature of Washington.

Sen.-elect Ted Cruz, the state’s former solicitor general, is taking Hutchison’s place in the Senate. He’s another one who’s unlikely to reach often across the aisle to Democrats. I hope he proves me wrong.

Hutchison, though, leaves a legacy of cooperation that used to result in important business getting done on behalf of the people who elected her.

Well done, Sen. Hutchison. This constituent – yours truly – appreciates your service to Texas and the country.