"Bribery at the heart of the Senate! I'm shocked. No wonder you don't like the Emperor; he became Chancellor in the first place on a platform of rooting out corruption like that. Well, 'not quite' or otherwise, it says here that the military placed such a blockade. In any case, a declaration has been made turning the blockade from a military matter to a political one on legal basis, on the authority of the Commissariat. Announcement to follow. Surprised they haven't made one yet, actually; they must have been distracted."
"No, says all will be explained in the announcement. It's a proclamation rather than a matter for debate."
Hmm. Blockades can be instituted for trading reasons, but that's not been very popular since... well, since the Battle of Naboo, really. The Imperials have used blockades for crime related matters before, though the distinction between that and military is blurry. They can be done for health-related reasons, or done in areas where there are mining quotas that are being exceeded... all tied into various complex rules and regulations- most of the time actually using legislation that existed in the Old Republic but that the Senate was simply too slow and inefficient to make use of without a dozen legal challenges that would render such action irrelevant by the time it would have been useful. Things are just more direct these days.
No reason to use Star Destroyers, of course, let alone brand new ones. Blockade duty is dull and time consuming; a job for frigates and other minor military craft. Unusual for one to be set up in this manner, though not in of itself illegal. Military might complain about being used so, but not in this case you would imagine.
I know why the Imperials are here, so I can narrow stuff down from there...
It's not for health reasons, such a quarantine if we all had the plague...
It's probably not for trade reasons, like the Trade Federation performance at Naboo...
So it must be criminal. Their original excuse was 'Rebels on planet' which is not enough, but they must have found something further...
We'll see if I can contest it. The Star Destroyers themselves are not accepting transmissions?
That time is now. The task force is broadcasting the following signal:
"Citizens of our glorious Empire, unfortunately it appears that the world of Lanzar still remains a grave threat to the peace and order in the galaxy. Situation after the recent bloody uprising remains yet unstable as the illegal goverment allows for criminal activities. Imperial Taskforce has stopped the illegal weapons from being smuggled into the planet, but it seems it is only the tip of the iceberg. We have just now uncovered the evidence of of the illegal trade of some of the most dangerous lifeforms in this world famous from its monstrous and vicious animals."
There follows a certain amount of taped evidence, including a raptor egg in an incibation chamber
"As you see, those beasts are incredibly dangerous killers and there is no way to predict how severe damage could they cause in the hands of criminal and terrorist elements, not to mention potential damage to diffrent ecosystems. As this is a clear violation of the "Act on the control of interplanar lifeforms movement- number 29981" and "Dangerous lifeforms protection Act- number 27589", as well as the "Executive Galactic Security Decree 115/B" among other legislation, Imperial Administration as represented by Commisar Melkor Esgabath hereby issues a temporal security decree, affecting the Lanzar system, enforcing a Class C planetary quarantine, immediately coming into force. All non-military vessels are hereby permitted from accessing the Lanzar system as well as leaving the system without authorization from the Imperial Administration, provided only after the examination from qualified personnel according to quarantine procedures. Current self-claimed "government" of Lanzar is required to take all steps necessary to stop the illegal activities. If local authorities fail to conform to this decree and refuse cooperation to ensure the elimination of illegal trade, there will be further consequences.
Only if the threat to galactic security is undoubtely fully eliminated shall this decree be terminated. After a month from this day a special commitee will review the need for its continuation.
Imperial Administation, as led by his Majesty Emperor Palpatine, always stays vigilant to ensure the safe and secure society and its progress. Imperial Order shall rule supreme, even on the most uncivilized worlds. All those that dare to threaten it shall suffer the consequences as the reaction will be swift and adequate.
Long live the Empire!"