With Mitt Romney abroad, his vice presidential contenders go on the attack

With Mitt Romney overseas, his team has dispatched an army of vice presidential contenders to swing states around the country to campaign in the presumptive GOP nominee's place.

The Number Two spot on the ticket usually plays the attack dog role and these campaign stops will be seen as try out roles for running-mate wannabes.

Louisiana Gov. Bobby Jindal, Virginia Gov. Bob McDonnell, Sens. Marco RubioMarco Antonio RubioGOP Senate candidates trade barbs in brutal Indiana primary Students gather outside White House after walkout to protest gun violence Overnight Energy: Senate confirms Bridenstine as NASA chief | Watchdog probes Pruitt’s use of security detail | Emails shine light on EPA science policy changes MORE (R-Fla.), John ThuneJohn Randolph ThuneHouse, Senate GOP compete for cash Overnight Tech: Alleged robocall kingpin testifies before Congress | What lawmakers learned | Push for new robocall rules | Facebook changes privacy settings ahead of new data law | Time Warner CEO defends AT&T merger at trial Senators grill alleged robocall kingpin MORE (R-S.D.) and Rob PortmanRobert (Rob) Jones PortmanTax rules will be subject to more OMB review under new memo Ending sex trafficking tomorrow requires preventing child abuse today Doctors bristle at push for opioid prescription limits MORE (R-Ohio), former Minnesota Gov. Tim Pawlenty, and Rep. Paul RyanPaul Davis RyanLieu rips Ryan after Waffle House shooting: ‘When will you stop silencing us?’ To succeed in Syria, Democrats should not resist Trump policy House Republicans prepare to battle for leadership slots MORE (R-Wis.) are among those making appearances for Romney.

Several of these men are said to be top contenders for the running mate job. Other names that have gotten buzz, but are missing, are Sen. Kelly AyotteKelly Ann AyotteAudit finds US Defense Department wasted hundreds of millions of taxpayer dollars US sends A-10 squadron to Afghanistan for first time in three years No, the US did not spend million on a gas station in Afghanistan MORE (R-N.H.) and New Jersey Gov. Chris Christie. Ayotte, however, will be joining Sen.s John McCainJohn Sidney McCainRomney forced into GOP primary for Utah Senate nomination Trump considering pardon for boxing legend after call from Sylvester Stallone GOP poised to advance rules change to speed up Trump nominees MORE (R-Ariz.) and Lindsey GrahamLindsey Olin GrahamKorean peace talks pose new challenge for Trump GOP sold Americans a bill of goods with tax reform law Republicans divided over legislation protecting Mueller MORE (R-S.C.) on of swing states that could face defense cuts under sequester.

Jindal, who's campaigning in Iowa before moving on to Florida on Saturday, has emerged as one of Romney’s fiercest and most visible surrogates. The governor has also been one of President Obama’s harshest critics — a role he has played since his withering attacks against the federal government following the BP oil spill in the Gulf of Mexico.

He was joined in Iowa by McDonnell, whose running mate prospects had been said to have fallen, especially after he was tapped to lead the platform committee at the Republican National Convention. His reemergence on the campaign trail will likely lead to speculation he's risen in the eyes of Team Romney. Jindal is seen as a top contender for the spot.

Romney has said he won't name a running mate while he's overseas. The only time line his campaign has given is to say the choice will be announced before the Republican National Convention begins in Tampa, Fla., on August 27.

Rubio also has seen his stock rise and fall as a possible vice presidential candidate. Recently he’s been on the upswing, as some in the party have said Romney’s struggles during his foreign trip might mean he should shirk a safe vice presidential pick for a candidate with more upside.

The freshman senator will be campaigning for Romney in the swing-state of Nevada and in Iowa this weekend. Rubio is the only candidate Romney has confirmed is being vetted. The others are known only to the presumptive nominee and Beth Myers, his aide leading the vetting team.

Myers added fuel to the VP fire on Friday when she tweeted out a list of suggestions for people to follow on Twitter that mirrors the likely vice presidential shortlist.

The names included: Ayotte, Pawlenty, Christie, Jindal, Rubio, Ryan, Former House Speaker Newt Gingrich, Portman, McDonnell, former Secretary of State Condoleezza Rice, Thune, New Mexico Gov. Susanna Martinez, and former Sen. Rick Santorum (R-Penn.).

Some of the names — like Gingrich and Santorum — are highly unlikely to be on the list, given the contentious Republican primary and their limited contact with Romney since he became the presumptive GOP nominee. Martinez was an early contender whose name sparked a great deal of buzz but she has told New Mexico papers she's not interested in the job. Rice's name skyrocketed up the list when the influential website the Drudge Report listed her as a favorite.

Neither woman is set to campaign for Romney this weekend.

Meanwhile, Ryan, the House Budget Committee chairman, will join Republican National Committee Chairman Reince Priebus on a bus tour through Wisconsin on Sunday, according to ABC News.

And Portman, said to be a top VP contender, has campaign stops scheduled in Ohio and Pennsylvania this weekend and on Monday.

Pawlenty, who's another leading contender, will campaign for Romney in North Carolina over the weekend.

And Thune, who's seen as dark horse VP candidate, was part of the GOP’s “you didn’t build this” offensive in Virginia on Thursday and will open a Romney campaign office in the state over the weekend.

Romney returns from his trip on Wednesday.

— Alicia M. Cohn contributed