Six vulnerable senators are feeling the heat of Election Day fast approaching. The six most vulnerable senators in the upcoming election, according to the Cook Political Report, are all first-term Republicans in split states. How have the Senate bills sponsored by these endangered Republicans changed from the beginning of this Congress in early 2015 to now?

There are two diverging tracts. Some of these senators are taking a turn to the right in an attempt to consolidate the fractured Republican electorate or fend off primary challengers. Others are voting more moderately to appeal to independent or even Democratic voters.

These varying strategies all have the same end goal in mind, but the Republicans’ Senate majority currently rests on a thin 54–46 margin. Losing either four or five of the 34 seats up for grabs this November would cost the party control of the Senate.

Mark Kirk of Illinois

Kirk, ranked in GovTrack’s ideology analysis as the most moderate Republican senator, has been trying to showcase those bipartisan bona fides in recent months. He was the first GOP senator to “un-endorse” presumptive Republican presidential nominee Donald Trump in June, saying Trump’s racially-motivated criticisms of a Mexican-American judge was the last straw. He was also the first Republican senator to meet with President Obama’s Supreme Court nominee Merrick Garland in March, who most Republicans refuse to hold hearings or a confirmation vote on. This strategy makes sense for Kirk’s home state of Illinois, the only one of the six senators from a blue state instead of a purple one.

Kirk’s two bills introduced in the past two months have been similarly nonpartisan. S. 3052, the Veterans Transplant Coverage Act, would guarantee that living donor transplants are covered by insurance provided by the Department of Veterans Affairs (VA), after a man in Texas made headlines for being denied coverage for that reason after a kidney transplant in June. S. 2925, the Requiring Accountability and Inspections for Dining Service Act, also addresses problems at the VA, to make sure kitchens and dining areas at VA medical facilities are up to code.

Kirk’s last sponsored bill that seems explicitly partisan in its support was S. 2740 in April, to prevent the release of almost any suspected terrorist detainees from the Guantanamo Bay detention facility in Cuba. The issue has become a lightning rod in the War on Terror, with Republicans believing it serves a vital national security purpose and Democrats led by President Obama largely seeking to shut it down, saying the torture committed there gives the U.S. a black eye on the world stage. Kirk’s bill has attracted eight cosponsors, all Republicans, but hasn’t yet received a vote in the Senate Armed Services Committee.

Ron Johnson of Wisconsin

Johnson’s most recent bill is about as bipartisan as anything in Congress these days. S. 3072, the Countering Terrorist Radicalization Act, was introduced in June a mere four days after the Orlando massacre. Its companion bill in the House passed the House in a 402–15 vote last month, though it has yet to receive a Senate vote.

As GovTrack Insider recently reported, the bill would have the Department of Homeland Security train local and state officials on how to more quickly identify and handle terrorism threats, create a new Counterterrorism Advisory Board in the federal government, and increase governmental communications techniques intended to counter the message of groups like ISIS and combat the spread of violent extremists.

His previous bill, introduced in May, is S. 3011, the Bolster Accountability to Drive Government Efficiency and Reform Washington Act. The bill contains provisions from 19 mostly-bipartisan bills that have been voted out of the Senate Homeland Security and Governmental Affairs Committee that Johnson chairs. This includes banning taxpayer-funded oil portraits and stopping Social Security payments to dead people. (The deceased often continue to receive payments by mail even after passing, due to agency lag times in updating their systems.)

Pat Toomey of Pennsylvania

Unlike his Wisconsin or Illinois counterparts, who seem to be showcasing their moderate leanings in this election year for their swing state voters, Toomey is not afraid of introducing clearly-conservative bills. His most recent from late June was S. 3100, the Stop Dangerous Sanctuary Cities Act, which would withhold federal funds from municipalities that protect undocumented immigrants from prosecution or deportation.

In an election year that has arguably been defined more by immigration than any other issue, this has been one of the most defining components. Republicans point to murders and other crimes such as child sexual abuse committed by immigrants supposedly “sheltered” by these cities. Most Democrats say the approach is more humanitarian and to vote otherwise would “undermine” local law enforcement. The bill received a Senate vote on Wednesday, where it received more “yes” than “no” votes by 53–44, yet failed to meet the 60 vote threshold needed to advance.

However, the bill he introduced before that was a piece of gun control legislation, one of the signature issues of congressional Democrats. S. 3069 would have the Department of Justice create a list of likely potential terrorists in the U.S., which could then be used to prevent sales of guns, or other weapons such as explosives. (The blocked sale would be dependent on a judge determining probable cause of terrorist activity, plus the would-be buyer would have the right to a legal appeal.) Most of Toomey’s fellow Republicans oppose the bill on the grounds that such a list could be overly broad.

Kelly Ayotte of New Hampshire

Ayotte’s bills had been fairly conservative prior to a few months ago, including bills to circumvent President Obama’s nuclear deal with Iran, preventing transfer or release of detainees at Guantanamo Bay similar to the aforementioned Mark Kirk bill, and prevent the Internal Revenue Service from targeting organizations based on certain beliefs as the IRS had under Obama for certain Tea Party-affiliated groups. (To be fair, she had also introduced some non-conservative bills such as the Allowing Greater Access to Safe and Effective Contraception Act.)

Since mid-April or so, though, Ayotte’s bills have been very nonpartisan. There’s the bill to make a commemorative coin out featuring the face of deceased astronaut Christa McAuliffe, a bill to help slow the rate of lung cancer in women, and the Working Families Relief Act to expand tax incentives for employer-provided dependent care assistance.

Rob Portman of Ohio

Portman, from what many now consider to be the most important presidential swing state, has also been taking a similarly non-confrontational tact. His most recent bill S. 3111, the Senior Tax Hike Prevention Act, does pretty much what its title implies, renewing a medical expense deduction for those aged 65 and older. He previously introduced S. 2971 in May, the National Urban Search and Rescue Response System Act, which would institute legal guarantees that private citizens who leave their jobs to help people in affected areas of local natural disasters can’t be fired as a result, after a FEMA report determined that 11 percent of search-and-rescue team members are private citizens.

Marco Rubio of Florida

Rubio, who insisted for well over a year that he would not be running for reelection in order to seek the Republican presidential nomination, a stance he maintained for months even after dropping out in March, reversed course in June and announced he would run after all. Analysts say this significantly increases the odds of Republicans maintaining the seat, as Florida is trending more blue and Rubio was seen as more electable than the other GOP contenders.

As a result, unlike the other five senators discussed above, Rubio was not introducing legislation over the past few months with an eye towards reelection prospects. (Some cynical observers say that Rubio likely knew he would run for reelection long before publicly announcing so.) Rubio has not introduced any legislation since announcing his reelection bid.

Bills he’d sponsored in the three-month interim period between dropping out of the presidential race and officially running for Senate again include S. 2752, the Preventing Iran’s Access to United States Dollars Act, a would-be economic sanction in an attempt to rectify what Rubio and most Republicans consider the ill-conceived nuclear deal last year with Iran. Another sanctions bill against Venezuela — S. 2845, the Venezuela Defense of Human Rights and Civil Society Extension Act — was introduced and passed the Senate by an anonymous voice vote in April.

This article was written by GovTrack Insider staff writer Jesse Rifkin.