Estuardo Rodriguez told Newsweek that a recently resurfaced 2011 TV interview with Buttigieg went to the "root of why there may be a lack of interest" in him among minority voters.
The former national security adviser has so far refused to testify to House investigators, even threatening legal action if he is subpoenaed.
South Bend Mayor Pete Buttigieg replaced Warren in second place surges to second after former Vice President Joe Biden.
The poll was conducted by conservative-leaning Rasmussen Reports, which regularly finds a higher approval rating for Trump than other major polls.
Morning Consult pollsters found the former Massachusetts governor had "no measurable support" among Democrat-leaning voters.
A new poll released by the University of Texas at Tyler indicated that Texas voters favor incumbent President Donald Trump for the 2020 presidential election over every single one of his challengers from the Democratic Party.
Polling Data from NPR and PBS NewsHour says nearly two thirds of Americans won't be swayed by new information and will remain firm on their opinion concerning the Trump impeachment inquiry.
The poll also found South Bend Mayor Pete Buttigieg leading the pack of Democratic candidates in Iowa.
Of those polled, 51 percent felt that Trump was wrong and should be removed from office, while 19 percent said that he was wrong but should retain his elected position.
Pete Buttigieg and Kamala Harris also had leads over the president, within the poll's margin of error.
New polling data indicates Trump will stay in office throughout his first term although public impeachment hearings have just begun.
Andrew Feldman questioned whether the United States was ready to elect a female president on Rising with Krystal & Saagar yesterday.
The results of a Washington Post-ABC News poll released Tuesday showed four Democratic presidential contenders winning by more than 10 percentage points in hypothetical match-ups against President Donald Trump.
I don't know what's up with the Fox poll," Hannity said. "I look at their poll, I'm like, okay, you're sampling—oversampling Democrats by eight points."
Nearly two-thirds of U.S. voters said they are not better off financially since Donald Trump took office, a new poll of likely voters finds.
The poll showed Clinton would be a head of Trump in the polls if she ran in 2020, with the real Democrat candidates also polling well against the president.
The president's approval rating among GOP supporters has fallen from 87 percent in July to 74 percent at the end of October.
The poll from Grinnell College showed that a majority of Republicans, evangelicals and rural voters thought that asking a foreign leader for help in an election was inappropriate.
Gallup has released the results of a new survey that shows a majority of American workers aren't satisfied with their jobs.
"When the question is about who has the highest chance of winning, Biden continues to dominate," a polling editor said.
Democrats believe Joe Biden is the best 2020 primary candidate on key election issues ranging from gun policy to immigration and the economy.
The president has come under fire from Republican lawmakers over his Syria troop withdrawal, allowing Turkey's invasion of Kurdish areas.
Warren tops the Democratic candidate field with 28 percent of the vote while Sanders comes in second with 21 percent. Biden, who has maintained his status as Democratic front-runner since entering the race in the spring, has fallen to just 18 percent.
The Ukraine affair and the threat of impeachment is eroding Republican support for the president in North Carolina.
The Democratic senator is ahead of the president when voters consider how health and age might impact their effectiveness in the White House.
The survey of 2,495 Americans by CBS News and YouGov found that 63 percent believed the Trump White House should cooperate with the impeachment probe.
"New Fox Poll shows a '40% Approval Rating by African Americans for President Trump, a record for Republicans,'" Trump tweeted last November. "Thank you, a great honor!"
A poll conducted among Wisconsin voters last week showed that the former vice president had a 9-point lead over President Trump.
Vermont Senator Bernie Sanders maintained his polling lead of all 2020 Democratic candidates among college students, while former Vice President Joe Biden was overwhelmingly ignored in a recent survey.
The survey found that 45 percent of U.S. adults support the House of Representatives voting to impeach Trump.