The union's members could agree to set appropriate boundaries, e.g. not defending staff who break the law. There are two unions representing metro train driver

The union's members could agree to set appropriate boundaries, e.g. not defending staff who break the law. There are two unions representing metro train drivers in London, and I have little respect for RMT since they've gone on strike to defend a driver who was sacked for turning up drunk to work[1]. The other union (ASLEF) seems more reasonable. When an issue is important to both unions (e.g. pay for nighttime services) they wield considerable power. If only RMT strike, there's significant disruption but trains still run. [1] https://tfl.gov.uk/info-for/media/press-releases/2015/february/lu-urges-rmt-members-to-vote-no-in-alcohol-ballot https://tfl.gov.uk/info-for/media/press-releases/2015/februa... / https://www.theguardian.com/uk-news/2015/mar/07/london-underground-workers-tube-strike-sacking-tfl https://www.theguardian.com/uk-news/2015/mar/07/london-under...