en.wikipedia.org/wiki/England%27s_difficulty_is_Ireland%27s_opportunity

The sentence gives the date as 1868, but the referenced London Review item is dated 23 September 1865.

Evidence:

• A scholarly article in American Nineteenth Century History cites the relevant source as "London Review, September 23, 1865, 319."
• The Google Books record for the cited page is the page in Volume 11 of The London Review of Politics, Society, Literature, Art, & Science; contemporary bibliographic listings place Volume 11 in 1865, not 1868.

So the publication being referred to was from 1865, making the article's year incorrect.