Mitt Romney’s campaign is publicly arguing that the methodology of a WaPo/ABC poll tainted its finding that his national numbers are tanking. However, polling experts who talked to TPM say that the survey is in line with a broad set of evidence that Romney’s general election appeal is declining — even if the poll’s approach is less than ideal.

The poll in question couldn’t have looked much worse for Romney’s presidential hopes. While it indicated he was still strong in the primary, his national numbers showed a rapid fall with Obama leading him 51-45 among registered voters. Romney pollster Neil Newhouse says these top line numbers should be disregarded because the question came after a series of queries referencing various recent stories surrounding Romney, including whether voters think his wealth is a positive or negative, whether they think he did more to create or cut jobs at Bain Capital, whether they feel his 14% tax rate is fair, and whether his Mormon religion affects their views of his candidacy.

“The poll introduced specific negative information about Governor Romney immediately prior to asking the ballot match-up against President Obama,” Newhouse wrote. “While I certainly understand the difficulty of designing a questionnaire to learn as much information as possible about a campaign, and the compromises that sometimes have to be made, the questionnaire design used by the Post/ABC Poll in this case is seriously flawed.”