Most Swedes will be unaffected by the travel ban. However, some will be ineligible for the Visa Waiver Program (VWP), and will therefore be unable to travel using ESTA. Most of these people will be able to travel to the US using a B visa.

VWP ineligibility

Unrelated to the "travel ban" enacted by the current administration (which is currently blocked by a court order), the previous administration enacted a restriction on the VWP. Travelers who have traveled to any of seven countries on or after March 1, 2011, are ineligible for the VWP. In addition, being a citizen of any of four countries is also disqualifying. These restrictions were already in place when you last traveled to the US in December 2016.

Nationals of VWP countries who have traveled to or been present in Iran, Iraq, Libya, Somalia, Sudan, Syria, or Yemen on or after March 1, 2011 (with limited exceptions for travel for diplomatic or military purposes in the service of a VWP country).

Nationals of VWP countries who are also nationals of Iran, Iraq, Sudan, or Syria.

There are exemptions available for those who traveled to these countries for diplomatic or military reasons, or perhaps for other reasons:

If an individual who is exempt from the Act because of his or her diplomatic or military presence in one of the four countries has his or her ESTA denied, he or she may go to the CBP website, or contact the CBP information Center. The traveler may also apply for a nonimmigrant visa at a U.S. Embassy or Consulate.

Certain other travelers who fall under this restriction may qualify for a waiver of the requirements. More information about possible waivers is forthcoming.

Source: https://travel.state.gov/content/visas/en/visit/visa-waiver-program.html

Inadmissibility

People who are ineligible for the VWP may apply for a B-1 or B-2 visa to travel to the US instead. However, the ban enacted by executive order 13780 may make some of these people entirely inadmissible to the US for a period of time. The relevant provision of the order is currently blocked by a court injunction, however, so it doesn't affect anyone right now.

Among the provisions of that order is one that allows affected dual citizens to travel using their passport from an unaffected country, so again, most Swedes who can't use the VWP as described above will continue to be able to travel to the US with a B visa. Section 3(b)(iv):

(b) Exceptions. The suspension of entry pursuant to section 2 of this order shall not apply to:

... (iv) any dual national of a country designated under section 2 of this order when the individual is traveling on a passport issued by a non-designated country;