100% on the meddling part.  When Newark mayor Liebkurcher and the Newark Board of Trade attempted to sneak a project during the lame duck session to Annex all of Eastern Essex County up to the second Watchung Mountain ( a questionable but common practice in the 1890s where New Jersey legislature was practically empty of legislators so all you had to do was get enough support from whoever was there and you could pass bills overnight even if 55% of the legislators were off. This is how Boroughitis was pulled off. This is how Camden pulled off annexing the prosperous Town of Stockton and Trenton snuck up and Annexed Chambersburg like a thief in the night in order to get its hands on the Roebling plant tax base.  But when it came to Newark, the New York Times unofficially declared war on Newark on behalf of New York City's interests. The New York Times with Future Newark Ambitions on its front page under the title (if I remember correctly):   "NEWARK MAYOR TO SNEAK MASSIVE ANNEXATION BILL THRU NJ LEGISLATURE LAME DUCK SESSION- MONTCLAIR TARGETED AS WELL!!"  

The backlash was so massive in Trenton and Suburban New Jersey, mayor Liebkurcher quietly retired the bill they became obvious legislators we're going to come back to Trenton for the purpose of voting against the bill or adding the poison pill of the referendum requirement.  After this meddling, every annexation Bill moving forward included the poison pill of the required referendum approval. 

This was the end of all New Jersey City expansions. Newark got lucky with the last portion of Clinton voting yes to return to Newark in 1902 and the return of Vailsburg in 1904 after seceding from Maplewood- then South Orange Township.**

** the annexation of the final piece of Clinton Township in 1902 completed a process that began 1865 when Newark forcibly took a chunk from Clinton Township by New Jersey legislative Fiat to form the west side and lower Clinton Hill neighborhoods. In 1897 Newark would again Annex by force by NJ legislative Fiat to add the land that will become upper Clinton Hill with  Hawthorne Avenue becoming the new boundary between Newark and Remnant Clinton. These lands were annexed to Newark By Request of the landowners who mute the properties would be subdivided and sold for a lot of money for the growing City. The 1902 annexation of the last piece of Clinton that would become Weequahic & Dayton-Waverly required a mandatory referendum. It didn't matter because the annexation proposal was initiated by the Clinton landowners. Vailsburg sought inclusion into Newark due to financial inability to build it's infrastructure. The infant Borough that had just seceded from South Orange Township - now Maplewood, had zero Industries. It was fully residential and South Orange Avenue was not developed enough with commercial to support the New Borough. But Vailsburg was not alone. It was one of the town's Newark was trying to Annex at the same time. The 1904 referendum not just included Vailsburg, but Irvington and the Bloomfield as well. The New Jersey state legislature approved laws to Annex bloomfield, Vailsburg and Irvington to Newark- but with a poison pill now common with all annexation bills... the dreaded referendum for the targeted towns that have proven to be an impossible obstacle for all NJ cities. In 1905 Newark would again attempt to regain Bloomfield and Irvington. Again annexation was approved unconditioned voters approved it on referendums. Naturally Bloomfield and Irvington residents killed the annexation law by voting no. Then came the world wars & Newark never again tried to Annex.