"Terrorist" as already suggested is thrown around a lot nowadays. One party may consider a group to be terrorist while some other party might view them as revolutionaries or Freedom fighters.
However, one undeniable fact, despite the ambiguity in the definition of terrorism , is that if you support factions who deliberately attack civilians, you support terrorism.
Iran, since the Islamic revolution, has followed the policy of ideological export. The main emphasis is on exporting the revolution to other states of the region and destabilize their existing regimes. Almost always it follows Proxy-Insurgency style covert warfare rather than outright conventional war.
Support and Creation of Proxies abroad
For Iranian backed proxies nowadays, we see:
- Anti-Government Elements in Bahrain who mostly happen to follow Shia Islam,Iran's official sect.
- Houthi rebels in Yemen.
- Shia Militias in Iraq
The Houthis and Dissidents of Bahrain are considered terrorists by their respective regimes. The Shia outfits were considered the same by Saddam regime of Iraq until US toppled Saddam and installed Shia government in Iraq. Now the Iraqi militias are right hand of Iraqi government in fight against ISIS but have been accused of similar terrorist acts by their Sunni countrymen and foreign powers.
Direct Support for Terrorist organizations
For directly supported foreign organizations who are considered terrorists by one or more countries in the world, we see:
- Hezbollah
- Hamas
- Palestinian Islamic Jihad
These organizations are classified as terrorist factions by several countries in the world. It must be noted however that many people (Especially from perspective of Iranian hardliners who whole-heartedly support their government's support of such organizations) in the region consider them to be freedom fighters and consider their attacks on civilians, a reaction to Israeli attacks on Palestinian civilians (Which may not be deliberate but are portrayed as deliberate by people who have a vested interest in that kind of portrayal. That doesn't mean that all such attacks are collateral damage). It must however also be noted that these organizations have deliberately struck several times civilians of nations they consider their enemies.
Direct Actions
Finally we hit the last spectrum, which is direct state-level covert operations/black-ops/terrorist-operations, choose your word.
Iranian Revolutionary Guard is responsible for operations abroad and many of them have caused them to be labelled a terrorist organization by US. For example:
- IRG was accused of carrying out an attack on Israeli ambassadors in India by Indian Police.
- Two IRG officials were arrested in Kenya, plotting an attack on Western and Israeli targets.
- US considers Iran to be responsible for 1998 US Embassy Bombings, USS Cole Bombing, Ties between Iran and Al-qaeda, supporting Afghan Taliban
- Germany considers Iranian intelligence to be directly involved in Mykonos Hotel murders.
- Argentinian Authorities believe Iranian government carried out 1994 Jewish center bombing in the country through their proxy Hezbollah.(Shout out to Colin Zwanziger for pointing it out).
Curious Case of ISIS
ISIS isn't the only terrorist organization in the world. The sole reason that Iran is fighting against them is because they consider Shias to be heretic and fit to be killed as they have shown. Iran is also protecting the so-called Shia chain (Iran~Iraq~Syria~Lebanon) by fighting against ISIS.
ISIS isn't some magical monster, fighting against whom instantly absolves you of all your other crimes. It doesn't absolve the Kurdish militias of their attacks on civilians, it doesn't absolve the Shia militias of their attacks on civilians, it doesn't absolve the Russians or the West of their attacks on civilians.
ISIS is a monster, no doubts about that but it is merely one of the many monsters on world stage. If ISIS was only anti-West, anti-Israel, make no mistake, Iran would have been on their side. (Similarly if ISIS was just anti-Assad and anti-Shia, US would have been on their side and would have called them moderate rebels.)
And since US is supporting FSA and other factions, It's easy to say that for Iranians, US is also terrorist. Same goes for every country in the world. The organization that fits your agenda is not a terrorist while the organization that is against you is a terrorist.
In conclusion, No Iran doesn't sponsor or support ISIS. Iran has actually been leading the real fight against ISIS from the beginning. Nevertheless, Yes, Iran supports terrorism. But so does every other major country in the world in one way or another.
Mr. Trump's statement just highlights the dilemma he was in given the attack on Iranian parliament. He was expected to convey sympathy to the Iranian people but at the same time, he had to point out Iranian backing of other terrorist organizations to please the anti-Iran lobby at home and allies in mid-East. He deftly managed that with his statement, with enormous help from Washington's PR and diplomatic corps no doubt. He showed sympathy but also bashed Iran which he recently called responsible for exporting sectarianism and violence in Mid-East during his last visit to KSA.