By Tim Devaney for The Hill

Medical marijuana advocates will descend on Capitol Hill Tuesday.

The advocates are in town for the National Medical Cannabis Unity Conference, which culminates in a lobbying day next week.

Currently, federal law prohibits any use of marijuana, including for medical purposes. But some states have lifted these restrictions within their own borders.

This has created a conflict between the federal government and state governments over marijuana enforcement.

The Obama administration took a hands-off approach to enforcement. But advocates are concerned the Trump administration will be more aggressive about going after marijuana companies in these states.

However, only Congress is in a position to completely lift the federal ban on marijuana through legislation. The advocates hope to make their case for lawmakers to issue a medical exemption.

Their push for legalization comes as Congress leaves town for a two-week recess, but hundreds of advocates plan to meet with Senate and House staff to discuss the issue.