U.S. Senator Heidi Heitkamp of North Dakota was supposed to be the keynote speaker at tonight’s Iowa Democratic Party Hall of Fame event in Des Moines. However, the party announced last night the senator would be unable to attend “due to a scheduling conflict.” At this writing, the Iowa Democratic Party has not responded to my request for further details on the cancellation.

Heitkamp’s planned Iowa debut could hardly have come at a more awkward time. Among the least progressive Senate Democrats on a number of issues, Heitkamp was noticeably absent this week as some 40 senators took part in a filibuster led by Senator Chris Murphy of Connecticut to force a vote on gun control measures. In 2013, she was one of just four Senate Democrats “who sided with the vast majority of Republicans to shoot down a bipartisan proposal to strengthen and expand background checks for gun purchases.” At the time, she said she opposed the bill drafted after the Sandy Hook mass shooting because “the focus should be on mental health issues, full and accurate reporting into the NICS database and ensuring that we are prosecuting criminals in possession of or trying to possess firearms. This conversation should be about what is in people’s minds, not about what is in their hands.”

In numerous social media postings this week, Iowa Democratic activists have criticized Heitkamp’s history of being a reliable vote for the National Rifle Association.

Even before last weekend’s massacre at the Pulse gay club in Orlando drew attention to the availability of assault weapons designed for use in military combat, I was expecting protests outside the hall and some heckling during Heitkamp’s speech, because of her ties to the fossil fuel industry. Opponents of the proposed Dakota Access (Bakken) pipeline have objected to giving Heitkamp such a prominent role in what is usually the Iowa Democratic Party’s second-largest event of the year. I enclose below a letter to the Des Moines Register by Wally Taylor of the Sierra Club.

Recent high school graduate Ryan McDaniel of Marshalltown will replace Heitkamp on tonight’s program, Jason Noble reported for the Des Moines Register. McDaniel won one of the Eychaner Foundation‘s fourteen Matthew Shepard scholarships this year. I’m excited to hear him speak.

Heads up, possible future presidential candidate spotters: U.S. Senator Heidi Heitkamp of North Dakota will speak at a major Democratic gathering in Des Moines on June 17. Alternating each summer between the capital city and Cedar Rapids, the Hall of Fame is typically the Iowa Democratic Party’s second-largest event of the year, after the to-be-renamed Jefferson-Jackson Dinner.

I enclose below today’s announcement from the Iowa Democratic Party and some background on Heitkamp, who was North Dakota’s attorney general before being elected to the U.S. Senate in 2012. Ticket sales (starting at $50) won’t be as brisk as for last summer’s event, which drew all five declared Democratic presidential candidates, but no doubt many activists will be interested to see Heitkamp in person. Her appearance may also draw some protesters, as she has been a “loud and proud” supporter of North Dakota’s oil extraction industry, and the proposed Dakota Access (Bakken) pipeline is a hot topic in this state’s environmental community.

This year’s Hall of Fame honorees include Senate Majority Leader Mike Gronstal in the elected official category, Iowa Federation of Labor President Ken Sagar as “outstanding supporter,” and State Representative Sharon Steckman for “oustanding leadership.” Scroll down to read the full list.

UPDATE: Should have mentioned that Heitkamp has the most conservative voting record in the Senate Democratic caucus, according to the Progressive Punch database. You can view ratings of votes on various types of issues here. Heitkamp has a “perfect” progressive record in only one category: fair taxation. As is common among Democrats representing tough states or districts, Heitkamp’s votes have become more conservative since Republicans gained a Senate majority (and therefore control over what comes to the floor).