[disgruntledphd2]

The EU Commission do not dictate policy.

This is a convenient fiction that the EU Council (i.e. the national governments) are very keen to retain, as it insulates them from the consequences of their decisions.

If you really wanted to be tactical about it, one should vote for a disjoint set of parties in the EU vs the national elections, as this would be more likely to lead to effective supervision and assessment of decisions.