Germany’s president, Frank-Walter Steinmeier, will address the Mexican Senate on Tuesday as part of a campaign to promote unity between democracies in the wake of Russia’s invasion of Ukraine. Steinmeier will be accompanied on his three-day trip by a cultural and business delegation. In Mexico City, he will also be made an honorary citizen. The trip was originally scheduled two years ago but was postponed due to the coronavirus pandemic. A planned visit to Costa Rica was cancelled because Steinmeier and his wife Elke Büdenbender were in London for the state funeral of Queen Elizabeth II. In Me…