Regional integration has significantly impacted sustainable development processes at the sub-national, supranational and interregional levels. Regions & Cohesion here has highlighted the complexity of interactions between policy arenas and actors/stakeholders at different levels of governance. Past articles have examined how regions can build bridges between policy arenas and levels of governance in different world regions with the objective of promoting sustainability.

As Regions & Cohesion begins its tenth year, it renews its commitment to these goals by focusing specifically on two important concepts in regional integration: coherence and cooperation. Policy coherence for development (PCD) is a tool that aims to address policy interactions that undermine sustainable development objectives. The journal has already published numerous articles on how this tool has been utilized and what its limits have been (see Koff, 2017; Larsson, 2018; Siitonen, 2017). However, numerous articles have highlighted incoherence for sustainable development, even though they do not specifically mention PCD. This has been prominently addressed in the fields of water (Kauffer, 2014), migration (Sacchetti, 2016), and health (Cruz, 2014), among others.

Of course, cooperation is a central response to incoherences for sustainable development. Regions & Cohesion has been fortunate to publish significant research on how actors establish cooperation (Faleye, 2016), what legal and political conditions foster cooperation (Mumme, 2019), and what positive impacts regional cooperation can have on communities (Deacon & Nita, 2013). The journal has also investigated the diffusion of sustainability norms through interregional cooperation (Dominguez, 2015).

The articles presented in Regions & Cohesion 10(1) highlight these two important themes. The first three articles address coherence issues related to sustainable development. The first article, written by Sandra Häbel, directly addresses PCD. It examines the European Union's commitment to PCD through analysis of its relations with Vietnam. This innovative research systemically unpacks EU political, development, and trade relationships with Vietnam through the lens of normative policy coherence for development in order to address the EU's commitment to PCD in these different arenas.

The second and third articles presented in this issue focus on sub-national incoherences for sustainable development in Mexico. The contribution by Torres-Jiménez et al. addresses a serious threat to sustainability—that is, the use of chemical fertilizers in agriculture. Through in-depth research with coffee producers in Veracruz, Mexico, the authors examine perceptions of bat guano for use as an organic fertilizer that would promote sustainability. While attitudes toward bats (in part based on appearances) affect these perceptions, the coffee producers who participated in the project discussed accessibility issues as well. The Mexican government promotes the use of artificial fertilizers through different mechanisms, but farmers must pay for organic fertilizers, like bat guano, from their own pockets.

This is followed by an article by Ana Melisa Pardo Montaño that addresses the relationship between migration and development through a local analysis of remittance uses. Through interviewing in Morelos, the author studies how households utilize financial resources gained through national and international remittances and compares these results to the 2016 National Survey on Household Income and Costs. She notes how remittances have limited impact on development in Morelos because they are utilized primarily to meet basic family needs.

The final two articles in this issue highlight cooperation and development. Diana Morales examines regional cooperation in Colombia through an empirical analysis of the Coffee Cultural Landscape of Colombia, a bottom-up regional cooperation process that resulted in a regional trademark and inclusion in the UNESCO Heritage Sites list. The research presented highlights the need to surpass studies of regional cooperation as an institutionalized system focused on policy effectiveness. Instead, she argues that regional cooperation is a process that includes actors and markets as contexts.

This is followed by a contribution in the journal's Leadership Forum by Fredy B.L. Tobing and Asra Virgianita that examines trade relationships between Indonesia, Chile, and Peru. The authors highlight contemporary opportunities for trade relationships between emerging economies within the context of “South–South” relations. However, they contend that they key to effectively fostering these relationships is the promotion of multi-track and multilevel diplomacy that includes both economic and political actors at different levels of governance. This strategy can potentially decrease dependence on trade relationships with the Global North.

These articles contribute to Regions & Cohesion's commitment to research on coherence and cooperation as a means to achieve sustainable development. However, they also underscore coherence and cooperation as defining characteristics of sustainable development that further magnifies their significance.

The Editors