The piece does disclose at the end:
This blog post is part of a series produced by the Obama Administration, in recognition of the 50th anniversary of the historic March on Washington. To see all the other posts in the series, as well as Huffington Post coverage of the milestone anniversary, click here.
But this leads you to a mash-up of posts with no clear disclosure which are “produced” by the Obama Administration. I use quotation marks because I honestly consider this to be a political advertisement. I don’t suppose I protest its presence if the Huffington Post wishes to use their platform as such (for propaganda), but it ought to be in a separate “Special Advertising Section.” Read here at HuffPo