One Louisiana columnist was sarcastically blunt — the biggest threat to Sen. David Vitter’s, R-La, 2010 Senate campaign was averted last week when fellow Republican Gov. Bobby Jindal refused to endorse Vitter.Jindal’s had a tough year with endorsements. Two of his endorsed candidates lost elections earlier this year.One, Lee Domingue, lost a State Senate race right in Jindal’s backyard, Baton Rouge, and the other, Brent Callais, lost even after Jindal held a campaign event for him.The setback didn’t stop Jindal from endorsing his former executive counsel, Jimmy Faircloth, for a State Supreme Court election later this month.But Jindal turned heads last week when he refused to endorse Vitter.”We’ll make a decision whether we’ll get involved in that race once we get closer,” Jindal said in an interview with Politico last week. “We haven’t made that decision yet.”State Democrats were quick to blast out a news release about the interview, as they have been throughout the year when Jindal’s endorsements didn’t pan out. “It’s not easy for a politician to transfer their popularity to someone else,” said Bob Mann, political communication professor and former communications director for Kathleen Blanco.Mann recalls races he was involved with when endorsements didn’t matter at all, when endorsements actually did unforeseen damage and when endorsements helped surge a candidate into victory.It’s the type of endorsement a politician offers, Mann said, which really makes a difference. If a politician’s endorsement is followed up by active campaigning on behalf of the candidate — holding a joint fundraiser or cutting a campaign commercial — the candidate stands to benefit.If the politician offers a passive endorsement — voicing only vocal support and forgoing the opportunity to help campaign or raise money — the difference might be negligible in the end. The important measure of support, Mann said, isn’t necessarily the endorsement — it’s how much Jindal campaigns for Vitter in the future, if he does at all. —-Contact Nate Monroe at [email protected]