Which group is abandoning Team Udall en masse?

This isn't really a surprise for the embattled Colorado Democrat, is it?

Originally from the Wall Street Journal:

After initially supporting incumbent Sen. Mark Udall (D., Colo.), through the first quarter of this year, oil and natural gas companies have since overwhelmingly supported his challenger, Rep. Cory Gardner (R., Colo.), over Mr. Udall.

Mr. Udall was among this election cycle’s top recipients of oil and gas money through March, having received $201,550 from the sector, according to Federal Election Commission data compiled by the Center for Responsive Politics up to March. At that time,  Mr. Gardner, who announced at the end of February his intent to challenge Mr. Udall after getting three other GOP candidates to bow out of a potentially bruising Republican primary, had received just $79,300 from the oil and gas industry for his House re-election bid.

Since Mr. Gardner entered the Senate race, the oil and gas industry has been pouring money into Mr. Gardner’s campaign. Between the first and second quarters, the industry gave $223,600 to Mr. Gardner and just $41,460 to Mr. Udall, according to the Center for Responsive Politics.

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