PR often crucial step in foreign M&A deals

"But you should also recognize that though it is a factual review, politics plays a role. I would advise Chinese companies that have to go through the CFIUS process to make sure they have the best local representation they can get, in terms of law firms, government relations firms, public affairs firms, and people who have the relationships, who know how the process works," he said.

He also noted that for companies, it is important to educate not only the CFIUS but also other stakeholders: members of Congress who may have an interest in the deal and local elected officials, like mayors in the city where they may do business. All those people have influence over the administration.

These efforts sometimes will not overcome the national security concerns, but they help frame the discussion in a more positive way for the CFIUS. And it is important to engage these people right away, according to Moeller.

For example, when it comes to visiting legislators, "do not be afraid to go to them and tell them a good story about what the company plans to do, because you don't want to wait until you get criticism to go to talk with them", he said.

There are positive changes, too. An affiliated company of Chinese equipment maker Sany Heavy Industry Co decided to sue the White House after US President Barack Obama barred its operations connected to wind farm projects. The victory in the US Court of Appeals raised eyebrows in both countries.

Ralls Corp, Sany's US affiliate, acquired four wind farm projects near a US naval facility in Oregon in early 2012. Obama then signed an order blocking the deal, citing national security concerns.

According to Moeller, the real significance of the ruling was "to create more transparency in the CFIUS review process", because the court said that any unclassified information the committee used to make a decision must be shared with the company involved. That was not the case previously.

"Now companies going before the CFIUS will have access to more information, and that will help companies prepare their CFIUS filings more accurately and effectively," he said.

Overseas M&A deals on the rise	Outbound M&A activity on the rise, survey says