Updated 5:15 p.m.

The playbook for Democrats as they look to seize control of the Senate is clear: tie vulnerable Republican incumbents to their party’s presidential front-runner, Donald Trump.

Republicans are responding with a message of their own: A Democratic Senate would make America less safe.

The National Republican Senatorial Committee (NRSC) launched a five-state digital ad campaign Thursday, releasing four similar Web ads set to run on YouTube and Facebook tying Democratic candidates to the approval of the Iran nuclear deal, the rise of the Islamic State and President Obama’s desire to close the military prison at Guantanamo Bay, Cuba.

The ads released Thursday target four Democrats. One is Sen. Michael F. Bennet of Colo., who is considered to be the sole Democratic incumbent in a competitive race this fall. The others are candidates Jason Kander of Missouri, Catherine Cortez Masto of Nevada and Joe Sestak of Pennsylvania. A fifth ad is set to be released next week.

Each ad tars the Democrat as “just another supporter of Obama’s weak foreign policy” and features a snippet of the candidate’s record on national security matters. The Kander ad, for instance, highlights a 2009 vote he took as a state representative against a resolution opposing the transfer of Guantanamo detainees to New Jersey. The Sestak ad features a clip of the former Navy admiral and congressman saying the Islamic State was “almost out of gas” in 2014. And the Bennet and Masto ads highlight their support for the Iran deal.

Kander now supports keeping Guantanamo open, and Sestak’s campaign said the “out of gas” clip was taken out of context. Sestak, who has led in recent Democratic primary polls in Pennsylvania, can take heart that Republicans are targeting him rather than Democrat Katie McGinty, who was endorsed Wednesday by Obama and has the backing of national party leaders.

Alleigh Marré, an NRSC spokeswoman, said the committee has committed “five figures” to the digital ads. The committee reported having $16.2 million to spend at the end of February.

The Democratic Senatorial Campaign Committee launched a “Party of Trump” ad campaign two weeks ago, kicking off what it promised would be a “sustained” effort with a Web ad featuring clips of Republican senators saying they would support the party’s presidential nominee. That committee reported having $13.6 million to spend on its candidates.