A meteoric rise in politics is often accompanied by a steep learning curve as a newly minted leader adjusts to the bright spotlight and responsibilities of higher office. An irresponsible tweet this week by newly elected U.S. House Rep. Ilhan Omar suggests she has work to do to achieve the gravitas that should be expected even from a first-term member of Congress. If she wants to be taken seriously by her new Capitol colleagues, the former one-term Minnesota legislator must take great care to avoid further unforced errors.

The troubling tweet is still posted on her @IlhanMN Twitter account, which suggests that neither Omar nor her staff sees the post as out of line. The language is off-the-cuff in tone but nevertheless flings a serious accusation at an influential political leader — U.S. Sen. Lindsey Graham, R-S.C. Graham has politically evolved from being one of President Donald Trump’s most vocal opponents to one of his most ardent defenders. Speculation abounds, especially on social media, about potential reasons for it.

What Omar did is to take one of the internet conspiracy theories and not only endorse it but fuel it. While using her Twitter account, she encountered a little-known podcaster’s video of Graham. In that TV clip from a 2015 CNN interview, Graham blasts Trump for being a “bigot,” among other things. The podcaster then added his own comment about the clip: “I can’t even imagine what they have on Graham.”

Omar retweeted the clip and the podcaster’s comment. Then she added her own rash conclusion: “They got to him, he is compromised!” The serious insinuation is that a sitting U.S. senator, one who served his country honorably in the military, may be the subject of blackmail. The evidence Omar has to back this up? Absolutely nothing. On Thursday, Omar defended the tweet in a CNN interview as “just an opinion.”

It’s notable that Omar didn’t walk back her comments but instead said she was sure many Americans agreed with her. By Friday afternoon, Omar’s tweet had been liked 19,295 times and retweeted 4,490 times. How many of her social-media supporters considered a more innocent and logical explanation: that Graham is up for re-election in 2020 and believes he’ll win by aligning himself with Trump?

It’s unfortunate that one very prominent Twitter user who resides in the White House often recklessly promotes information that is, at best, unvetted. While casual disregard for the truth is standard fare on social media, the bar should be elevated for those in whom voters have placed their trust — elected representatives. Trump’s behavior is an example to be avoided, not emulated.

If Omar doesn’t care about Graham’s reputation, she should care about what disregard for the truth does to her standing on Capitol Hill. Who will trust her? Who will want to work with her? Hamstringing her career so soon would be a real shame. The Star Tribune Editorial Board differs from Omar on a number of issues, but she has a formidable intellect, and her persuasive eloquence has the potential to move legislation.

A Republican, former Rep. Michele Bachmann, was taken to task a number of times in these pages, including for her “foolish attack on vaccines,” her support for a brutal crackdown by an Egyptian dictator, and her worries about anti-Americans stalking the halls of Congress. Bachmann’s careless words undermined her political career, and in particular made it difficult for her to pass legislation. Her mistakes should not be repeated.

The Editorial Board did not endorse Omar, but she can be an effective, influential leader. More care with her future communications will serve her — and Minnesota — well.