The Note: Pennsylvania's primary a test for Democratic women More than 20 Democratic women are running, in 13 of states18 House Districts.

WASHINGTON, D.C. --

The TAKE with Rick Klein

They are off the sidelines. But that doesn’t mean they are players in the game – at least not yet.

If there’s going to be a “pink wave,” it basically has to start building in Pennsylvania, where primary elections are being held on Tuesday. There is perhaps no more important state to Democratic hopes to take over the House, and the state’s all-male – and 2-1 Republican – House delegation is virtually assured of looking a whole lot different in 2019.

More than 20 Democratic women are running, in 13 of the Keystone State’s 18 House districts. A few will almost certainly become members of Congress, and many will of course fall short.

One primary to watch closely for ramifications for the fall: the First Congressional District, in the suburbs north of Philadelphia.

Rachel Reddick, a 33-year-old mom, former Navy lawyer, and onetime Republican, is trying to defeat a wealthy, male Democratic opponent who moved back to the district to run.

Scott Wallace, 66, is the grandson of former Vice President Henry Wallace – he served a term as Franklin Delano Roosevelt’s vice president -- and his personal fortune has helped make him the favorite in the race to go up against vulnerable Republican Rep. Brian Fitzpatrick.

2018 may be remembered as a big year for women and for Democrats more broadly. But to get there, intriguing biographies and anecdotes need to turn into wins.

The RUNDOWN with MaryAlice Parks

Democrats' best bet for taking back the House in November is to have a big night in Pennsylvania.

Two other forces, in addition to the wave of female candidates, have put a number of seats in play.

First, there’s a brand new map. A court-ordered redrawing of the congressional map has made a number of Republican-held seats much more competitive and presented ripe pickup opportunities for Democrats.

By some estimates, five districts that are currently red are already leaning blue, because of the new maps and enthusiasm on the left.

Across the country, redistricting and gerrymandering continue to be major issues as parties zero in on the reality that whoever controls the statehouses will likely get to draw new maps in 2020 (a case before the U.S. Supreme Court could impact that a bit), and voters push back against leaders when maps slant too much.

Republican retirements and resignations in the state and have thrown the current party makeup for a loop, too. Without incumbents on the ballots, Democrats are hoping they’ll have an easier time.

The TIP with Benjamin Siegel

Billionaire Democratic donor Tom Steyer’s national campaign to flip control of the House and impeach President Donald Trump passed through northern Virginia Monday night, with a forum for a handful of the Democrats vying to take on vulnerable Rep. Barbara Comstock, R-Va., in November.

Amid light-hearted questions about Starbucks orders and preferred superpowers, five of the six Democrats in the primary took jabs at Comstock’s support for the GOP tax plan, the National Rifle Association, and President Trump. All five raised their hands when asked if they believe Trump is unfit for office.

"After 9/11, the worst threat to our democracy lived in a cave. Now he lives in the White House," Dan Helmer, an Army veteran who served in Iraq and Afghanistan, said. "I’m ready to vote to impeach him to defend democracy." State Sen. Jennifer Wexton, who is viewed as the frontrunner ahead of the June primary, was in Richmond for the state Senate’s special session and did not attend the forum.

Along with Helmer, former Obama administration officials Lindsey Davis Stover and Alison Friedman, infectious disease scientist Julia Biggins and former federal prosecutor Paul Pelletier fielded questions from Steyer.

WHAT YOU NEED TO KNOW TODAY

• President Trump gives remarks at the 37th Annual National Peace Officers' Memorial Service at 11 a.m.

• The president participates in a Senate Republican policy lunch at 1 p.m.

• Pennsylvania, Nebraska, Idaho and Oregon hold their 2018 primaries. Polls in Pennsylvania open at 7 a.m. and close at 8 p.m. EDT. Nebraska polls open at 9 a.m. and close at 9 p.m. EDT. Polls open at 10 a.m. and close at 10 p.m. EDT in Idaho. Oregon’s all-mail voting system closes at 11 p.m. EDT.

• You can read coverage of the primary action on ABCNews.com or on the ABC News app available on the Apple App Store, Google Play Store, Apple TV App Store, and Roku Channel Store. Don’t forget to sign up for Midterm Elections Alerts to get more coverage of this year’s election season from our powerhouse politics team.

• The Center for American Progress (CAP) holds its annual conference with elected officials Sen. Cory Booker, D-N.J., Sen. Bernie Sanders, I-Vt., and Sen. Elizabeth Warren, D-Mass., as keynote speakers at 9 a.m.

• GOP senators will ask Senate Majority Leader Mitch McConnell to expedite floor consideration of funding bills and nominees before the end of the fiscal year during the Senate Backlog Conference at 10 a.m.

• Sen. Lindsey Graham, R-S.C., hosts a briefing on the latest advancements in the fight against brain cancer in tribute to his friend and colleague, Sen. John McCain, R-Ariz., at 12:15 p.m.

QUOTE OF THE DAY

"I didn’t want to miss the opportunity to tell him how much his friendship meant to me. So that’s why I was out there this weekend. And while I was there, I said I was confident I was speaking for everybody in the Senate. And conveying our deepest respects to him for all he’s done for this country during a truly extraordinary life." - Senate Majority Leader Mitch McConnell on the Senate floor Monday night, paying tribute to Sen. John McCain after visiting him this past weekend in Arizona.

NEED TO READ

Pennsylvania highlights slate of four primaries Tuesday night. A score of retirements, jammed-packed ballots, brand new district maps and rising political stars will all combine to make Pennsylvania one of the most interesting states to watch this primary season. (John Verhovek and Adam Kelsey) https://abcn.ws/2IidAxS

President visits first lady Melania Trump in hospital after kidney procedure. The White House has announced that first lady Melania Trump underwent a procedure Monday morning at Walter Reed National Military Medical Center to treat a kidney condition. (Jordyn Phelps, Devin Dwyer and Cindy Smith) https://abcn.ws/2GeRGFS

‘Dozens’ of Marines augmenting US embassy security in Turkey, Israel, Jordan. The news comes on the same day that the U.S. opened its embassy in Jerusalem and at least 55 people were killed during protests in Gaza, according to Gaza's health ministry. (Stephanie Ramos and Elizabeth Mclaughlin) https://abcn.ws/2rGXnYI

EPA requested 24/7 security for Pruitt on day one, internal watchdog says. Environmental Protection Agency chief Scott Pruitt requested a 24/7 security detail when he was confirmed as administrator, according to a publicly released letter from an internal watchdog to members of Congress. (Stephanie Ebbs) https://abcn.ws/2rIwwL6

McConnell comes to McCain's defense on Senate floor: 'You’d rather be on his side than not.' McConnell has had a back-and-forth relationship with McCain, something he admitted to in his speech Monday, but he offered nothing but praise for the senator during his current plight. (Mark Osborne and Mariam Khan) https://abcn.ws/2Gfcb5a

Meghan McCain says her father's critics are 'going to have to answer for their own conscience' for caustic comments. Meghan McCain said on Monday that her father's critics are "going to have to answer for their own conscience" after a weekend war of words in which a conservative leader said the White House staffer who allegedly made stunningly disparaging comments about her father, Arizona Senator John McCain, is herself" a little bit of a victim here." (Meghan Keneally) https://abcn.ws/2GdBZ1H

A top Israeli soccer team adds ‘Trump’ to its name to honor US president. One of Israel's most famous soccer teams has renamed itself to honor President Donald Trump for his controversial decision to move the U.S. embassy to Jerusalem. (Dragana Jovanovic) https://abcn.ws/2wFm5xw

The EPA and White House attempted to block reports on a federal health study on a nationwide water-contamination crisis, after one Trump administration aide warned it would cause a “public relations nightmare,” from leaking, Politico reports. https://politi.co/2jTtaBg

The New York Times reports Vice President Mike Pence is trying to control Republican politics and Trump aides aren't happy about it. https://nyti.ms/2Inj4TX

The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.