hard line 
noun
An uncompromising adherence to a firm policy: he is known to take a hard line on sentencing policy for murder...
- Molotov favoured a continuation of the hard line in foreign policy, especially towards Tito.
- I know that Sharon is a hard line politician who won't give any ground, but the mood in Israel is changing and he won't be around forever.
- They may split the vote in a way that favours someone such as Maureen Gilroy who takes a hard line against issues of social equity.
adjective
Uncompromising; strict: a hard-line party activist...
- Many of the madrassas were run by Jamiat-e-Ulema-i-Islami, one of Pakistan's main hard-line religious parties.
- The parallel British demilitarisation of the province, will also be tough on hard-line unionists.
- You are never going to convert hard-line extremists by behaving properly, David concedes.
Synonyms
uncompromising, strict, diehard, extreme, tough, inflexible, immoderate, intransigent, intractable, unyielding, undeviating, unwavering, single-minded, not giving an inch
rare indurate