Lattimer Massacre
...that backlash from the 1897 Lattimer Massacre in Pennsylvania, an important event in the U.S. history of labor relations, resulted in the addition of some 15,000 new members of United Mine Workers of America union?
...that backlash from the <a href="./1897" id="mwnw" rel="mw:WikiLink" title="1897">1897</a> <b id="mwoA"><a class="mw-redirect" href="./Lattimer_Massacre" id="mwoQ" rel="mw:WikiLink" title="Lattimer Massacre">Lattimer Massacre</a></b> in <a href="./Pennsylvania" id="mwog" rel="mw:WikiLink" title="Pennsylvania">Pennsylvania</a>, an important event in the <a class="new" data-mw-i18n='{"title":{"lang":"x-page","key":"red-link-title","params":["Category:U.S. history of labor relations"]}}' href="./Category:U.S._history_of_labor_relations?action=edit&amp;redlink=1" id="mwow" rel="mw:WikiLink" title="Category:U.S. history of labor relations" typeof="mw:LocalizedAttrs">U.S. history of labor relations</a>, resulted in the addition of some 15,000 new members of <a href="./United_Mine_Workers_of_America" id="mwpA" rel="mw:WikiLink" title="United Mine Workers of America">United Mine Workers of America</a> <a class="mw-redirect" href="./Labor_union" id="mwpQ" rel="mw:WikiLink" title="Labor union">union</a>?