  Monitoring advertising around controversial issues is an important step in
ensuring accountability and transparency of political processes. To that end,
we use the Facebook Ads Library to collect 2312 migration-related advertising
campaigns in Italy over one year. Our pro- and anti-immigration classifier
(F1=0.85) reveals a partisan divide among the major Italian political parties,
with anti-immigration ads accounting for nearly 15M impressions. Although
composing 47.6% of all migration-related ads, anti-immigration ones receive
65.2% of impressions. We estimate that about two thirds of all captured
campaigns use some kind of demographic targeting by location, gender, or age.
We find sharp divides by age and gender: for instance, anti-immigration ads
from major parties are 17% more likely to be seen by a male user than a female.
Unlike pro-migration parties, we find that anti-immigration ones reach a
similar demographic to their own voters. However their audience change with
topic: an ad from anti-immigration parties is 24% more likely to be seen by a
male user when the ad speaks about migration, than if it does not. Furthermore,
the viewership of such campaigns tends to follow the volume of mainstream news
around immigration, supporting the theory that political advertisers try to
"ride the wave" of current news. We conclude with policy implications for
political communication: since the Facebook Ads Library does not allow to
distinguish between advertisers intentions and algorithmic targeting, we argue
that more details should be shared by platforms regarding the targeting
configuration of socio-political campaigns.
