The Broadcom-Qualcomm deal is dead, forbidden by a presidential order. It is a permanent ban that forbids any future acquisition, merger or deal with similar consequences. Broadcoms nominees for the Qualcomm board of directors have been disqualified by the same order.
The presidential order cites credible evidence that the deal might threaten national security. It does not go into detail, but the Committee on Foreign Investment in the US (CFIUS) said that Qualcomms leadership in wireless patents for 5G are key to national security. If Qualcomm is impeded in its R&D, Chinese companies will take the lead.
Qualcomm delayed the meeting of its shareholders by 30 days following the CFIUS inquiry. However, it has now been ordered to hold the meeting as soon as possible on March 23 after a 10-day notice period.
For more, you can read the presidential order and Qualcomms press release.