The Missouri Democratic Party has tapped U.S. Sen. Dick Durbin, D-Ill., to be the keynote speaker for the state party’s annual Jefferson-Jackson Dinner, to be held June 7 at the Renaissance Grand Hotel in St. Louis.

Durbin’s selection marks a rare instance when Missouri Democrats have reached across the Mississippi River to more-liberal Illinois for a major speaker. Over the past decade, the Jefferson-Jackson Dinner has become Missouri Democrats’ biggest fundraising event of the year, but the keynote guest often has been a Democrat deemed more moderate (like Sen. Jon Tester, D-Montana).

Durbin, now the Senate’s No. 2 as assistant majority leader (aka “majority whip”), is an unapologetic progressive and long has been a mentor to now-President Barack Obama, once Illinois’ junior senator. Durbin was first elected to the U.S. Senate in 1996, earlier serving in the U.S. House. He is up for re-election this fall.

“We are thrilled to welcome Sen. Durbin to Missouri,” said Missouri Democratic Party chairman Roy Temple in a statement. “Throughout his career, he has fought tirelessly for middle class families and promoted constructive dialogue, encouraging commonsense solutions. Missouri Democrats can look forward to an inspiring speech from one of our party’s finest leaders.”

Missouri Gov. Jay Nixon called Durbin “a national leader on the kitchen table issues most important to working Americans.”

But Sen. Claire McCaskill, D-Mo., may have offered up the best reason Missouri Democrats have invited Durbin to address what’s often the largest crowd of Missouri Democratic officials, union leaders and major donors.

"He knows better than most how important it is to energize our party for this year's elections, so we can keep building on the successes of the past several years,” McCaskill said.

Although she took note of Missouri Democrats’ strong statewide showing in 2012, losing only one statewide office, McCaskill’s comments also alluded to the disastrous turnout problem that Missouri Democrats confronted in 2010, which cost the party dearly.

Tuesday’s legislative override of Nixon’s veto of a tax-cut bill was largely possible because of the Missouri Republican Party’s huge majorities in the state Senate (veto-proof) and House (one short of veto-proof).

One key question may be whether state Rep. Keith English, D-Florissant — who provided the pivotal House vote that allowed the GOP’s override effort to succeed — will be welcome at the Democratic dinner.