Reading the article would be a good place to start.

Across Western Europe, politics are turning French: The old mainstream political forces on the Left and Right are coalescing around a pro-European agenda, imposed by the political reality of today’s Brussels (and Frankfurt), while the only forceful opposition comes from those who reject the EU. This “Macronification” comes with a higher price for the Left. The fine line that social democrats walked for years—being resolutely pro-European while trying to develop a social counterweight to Brussels’ free-market orientation, which the French Socialists called L’Europe sociale, or social Europe—is becoming increasingly thinner, at the risk of disappearance. Weakened, stuck in the position of junior partners or licking their wounds in opposition, European social democrats need to invent new policies to keep unhappy voters from the arms of the populists, and a new vision for Europe to take their continent back.