Wagner's music dramas differ from the 19th century Italian operas in what ways?
What influence did Wagner’s music have on nationalism?
What innovations in compositional technique, harmony, staging and production did Richard Wagner employ?
The second question in the body matches the title and is the best fit for this web site. The question about nationalism is really more of a political question that would fit better on History.SE. Please consider editing. Also, welcome to the site!
It sounds as if you are copying questions from a school homework assignment and asking us to do your homework for you.
I strongly doubt, that music is able to influence nationalism (more the other way round) and can't believe there exist research results supporting this.
@guidot, your doubts may be unfounded. The history of modern-era politics is literally bursting with examples of how states use all the arts to forward, support, and publicize a nationalistic agenda.
@jdv: While I agree, this does not help for the argumentation. As a composer of a genre which does not adapt easily to consumption of masses (Bayreuther Festspielhaus e. g. ca. 2000 visitors) and which nearly nowhere in the libretto provides statements connectable to nationalism, you have to combine the ouevre with heavy propaganda-wording from different sources. To make the composer responsible for the total effect is somewhat ambitious.
No one said "total effect". I think it's clear we are discussing multiple effective tools under various circumstances. I think it's instructive to consider what music and art some social and political movements considered un-worthy of the movement. What does this say about they stuff they promote, either implicitly or explicitly? My assertion is clear: your doubts that music has been used as a way to promote nationalistic interests are unfounded.
Wagner revolutionized opera through his concept of the Gesamtkunstwerk ("total work of art"), by which he sought to synthesize the poetic, visual, musical and dramatic arts, with music subsidiary to drama. He pretty much codified opera into what it is today.
He single-handedly popularized the Leitmotiv, which has become inextricably linked with the name Wagner. Composition utilizing Leitmotif has since become standard not only in opera, but also in modern film scores (the most recognizable example to the lay person is the recurring themes in the "Star Wars" film franchise).
Politically, he is remembered as an outspoken anti-semite, long after his death his melodies were adopted as theme music for the Nazi party, and therefore performances of his works are still discouraged in the state of Israel today.
Read all about it here:
This addresses the first question only, since I consider the second as subject of reference works and whole books.
The German Brockhaus from 1894, so a nearly contemporary work, offers this text:
Obwohl W. vielfach und heftig angefeindet wurde, namentlich von den Fachmusikern, so lenkte doch jetzt der glücklich beendete Deutsch-Französische Krieg von 1870 und 1871 die gehobene patriotische Stimmung ganz besonders auf ihn, weil man in seiner Behandlung alter deutscher Sagen eine neue specifisch deutsche Kunst erblickte.
While W[agner] was often and vigorously attacked, especially by professional musicans, the German-French war of 1870/71 with its lucky result directed the elevated patriotic mood especially on him, since one considered his treatment of old German legends as a new intrinsically German art.
So at least this article puts cause and effect the other way round.