Whether or not a president feels compel, or that he has the right to disclose information - classified or not, to Russia, or to any other foreign entity, his decision should always be governed by the need, the respect and the security to protect the sources of said information at all costs.
The United States(US) Presidency is a High Office that should be voided of gloating and boasting. All information privy to the Oval Office, should be treated with the highest of decorum.
Media reports that Donald Trump shared highly classified information with Russia during a meeting last week that included the Russian press, but precluded the US press, are deeply troubling. Such revelations could have a provocative negative impact upon the future of US intelligence gathering, while discouraging credible sources from sharing critical information with the US. Moreover, such revelations could place sources in deadly peril.
Information provided via credible, well informed and well placed sources, has always been a crucial link to the intelligence gathering services. If the trust of anonymous informants is betrayed, then intelligence agencies will inevitably suffer.
Therefore, while the appropriate checks are carried out to determine what sort of information Trump disclosed to the Russians, all measures must be taken to protect the identity and safety of sources of all US intelligence information.