Germany's would-be next chancellor, Friedrich Merz, won lawmakers' approval to loosen strict debt rules for higher defense spending as doubts mount about the strength of the trans-Atlantic alliance.

Germany's parliament approved plans for a massive spending surge on Tuesday, throwing off decades of fiscal conservatism in hopes of reviving economic growth and scaling up military spending for a new era of European collective defence.

Germany’s Bundestag, or Lower House of Parliament, passed a historic bill allowing it to sidestep its strict rules on debt to spend big on defence and infrastructure. Why is this move a big deal? And why does its timing matter?