Transcript for Gun Control Moves to Forefront of Presidential Race
In meantime, we turn to the race for the white house. Bernie sanders still in the race telling supporters overnight defeating Donald Trump is a priority. As trump now takes on the president, even as the president visits Orlando to meet with the victims' families the president now calling for action. His tenth visit to a community after a mass shooting pointing out the children of Newtown would now be finishing the fifth grade. ABC's Jonathan Karl has the latest. Good morning, Jon. Reporter: Good morning, David. National mourning over the Orlando massacre is giving way to political finger-pointing over who or what is to blame. One year, the escalator, one year, this is the one-year anniversary. Hopefully we'll make it a worthwhile year. Reporter: On the one-year anniversary of his campaign Donald Trump attacked president Obama for calling for gun control after he paid his respects to victims in Orlando. I held and hugged grieving family members and parents and they asked why does this keep happening? And they pleaded that we do more to stop the carnage. It's a tough situation. But he's largely to a large extent he's blaming guns and -- And I'm going to save your second amendment many, folks. Reporter: But on capitol hill there are signs of possible agreement on one gun issue. Of course, no one wants terrorists to be able to buy guns. Reporter: After nearly 15 hours of outrage on the senate floor Wednesday, the senate plans to vote next Monday on several gun control measures. Democrats want to ban anyone on a terrorist watch list from buying a gun. But republicans have instead called for a three-day waiting period to make sure the buyer is not actually a suspected terrorist. But the two sides are still far apart. The republican amendments are laughable written by the NRA and make this country less Cespedes. Reporter: Senator John McCain even said president Obama was directly responsible for the Orlando attack although later he said he misspoke, was not talking about the president personally but about his policies. The president's failure to address the threat of Isis has led to attacks on the united States. Reporter: Meanwhile, back on the campaign trail, trump is feeling new heat as he lags behind Hillary Clinton in the latest polls and one poll Clinton up 6, in another she's up 12 points. And now Bernie sanders says he stands poised to join forces with Clinton pledging in a livestream address he'll work to take trump down. I personally intend to begin my role in that process in a very short period of time. Reporter: Now sanders did not formally drop out of the race, concede or endorse Hillary Clinton, instead he said he plans to continue fighting to transform the democratic party all the way into the democratic convention and beyond. All right, Jon Karl with us live, Jon, thanks. Right to our political
This transcript has been automatically generated and may not be 100% accurate.